DEPARTMENT OF CONSERVATION-
Michael F. Byrne, Director
PB95-191268
. EPA No. 530-R-95-013a
Application of Geophysics
to
Acid Mine Drainage Investigations
Volume!
-
literature Review
'"- >< , -' „ «n/f
, -
-------
Table of Contents
Volume I
^
Page
EXECUTIVE SUMMARY v.
RECOMMENDATIONS vii.
I. INTRODUCTION
PURPOSE AND SCOPE 1.
ACKNOWLEDGEMENT 2.
II. ACID MINE DRAINAGE (AMD)
GENERAL DISCUSSION OF AMD 5.
GEOCHEMICAL SETTING FOR AMD 5.
GEOCHEMICAL AND GEOPHYSICAL RELATIONSHIPS
General Discussion 6.
Porosity, Permeability and Heterogeneity • 11.
Electrolyte Concentration 14.
Moisture Content 19.
Temperature 21.
III. APPLICATION OF GEOPHYSICAL METHODS TO AMD INVESTIGATIONS
GENERAL DISCUSSION 23.
OPTIMUM SAMPLING IN GEOPHYSICAL SURVEYS 24.
D.C. RESISTIVITY GEOPHYSICAL METHODS
GENERAL DISCUSSION
Basic Principles 26.
Equivalence and Suppression 27.
Survey Methods 29.
Array Electrode Geometries 30.
Depth of Investigations 32.
Comparison of Arrays 35.
Interpretation of Resistivity Data 36.
USE OF D.C. RESISTIVITY IN AMD INVESTIGATIONS
General Discussion 39.
Geologic Structure and Stratigraphy 40.
Ground- Water Protection Zones 41.
Aquifer Properties and Ground-Water Quality 41.
Fracture Systems 42.
Landfills and Waste Impoundments - 44.
Open and Filled Voids 44.
Long-Term Monitoring 45.
D.C. RESISTIVITY FIELD PROCEDURES 45.
MISE-A-LA-MASSE GEOPHYSICAL METHODS 47.
-------
Table of Contents
Volume I
Page
INDUCED POLARIZATION (IP) GEOPHYSICAL METHODS
GENERAL DISCUSSION 48.
USE OF IP IN AMD INVESTIGATIONS 52.
ELECTROMAGNETIC (EM) GEOPHYSICAL METHODS
GENERAL DISCUSSION 54.
VERY LOW FREQUENCY METHODS
Conventional VLF 57.
VLF Resistivity 58.
AUDIO-MAGNETOTELLURIC AND CONTROLLED
SOURCE AUDIO-MAGNETOTELLURIC METHODS 59.
FREQUENCY-DOMAIN SLINGRAM
AND GROUND CONDUCTIVITY METER METHODS 60.
TIME-DOMAIN EM METHODS 64.
USE OF EM METHODS IN AMD INVESTIGATIONS 65.
EM FIELD PROCEDURES 70.
SELF POTENTIAL (SP) GEOPHYSICAL METHODS
GENERAL DISCUSSION 71.
USE OF SP IN AMD INVESTIGATIONS 74.
SP FIELD PROCEDURES 76.
SEISMIC GEOPHYSICAL METHODS 77.
GRAVITY GEOPHYSICAL METHODS 84.
MAGNETIC GEOPHYSICAL METHODS 87.
GROUND PENETRATING RADAR METHOD 88.
BOREHOLE GEOPHYSICAL METHODS 89.
IV. REFERENCES
GEOPHYSICAL TEXTBOOKS 95.
GENERAL ENVIRONMENTAL, GROUND WATER
AND GEOTECHNICAL GEOPHYSICAL METHODS 97.
WATER QUALITY AND GEOPHYSICS 100.
CONVENTIONAL RESISTIVITY GEOPHYSICS 104.
MISE-A-LA-MASSE GEOPHYSICS 118.
INDUCED POLARIZATION GEOPHYSICS 119.
ELECTROMAGNETIC GEOPHYSICS 122.
SELF POTENTIAL GEOPHYSICS 127.
SEISMIC GEOPHYSICS 130.
GRAVITY GEOPHYSICS 133.
MAGNETIC GEOPHYSICS 135.
GROUND PENETRATING RADAR 136.
BOREHOLE GEOPHYSICS 138.
V. LIST OF ABBREVIATIONS 143.
u.
-------
List of Figures
Volume I
Page
1. Plot of specific conductance versus total dissolved solids 16.
2. NaCl equivalence concentrations chart 16.
3a. Potential and current distribution for resistivity array 31.
3b. Wenner array equipotential and current flow lines 31.
4. Electrode configuration D.C. resistivity with interpretation formulas 33.
5a. Electromagnetic response versus depth curves 63.
5b. Electromagnetic cumulative response versus depth curves . 63.
6. Schematic of seismic refraction ray-paths 79.
7. Field setup of shot points and geophones for seismic refraction 79.
8. Seismic ray-paths and time-distance plot for 2-layer model 82.
9. Matrix chart of borehole logging methods applicability 94.
Tables
Volume I
Page
1. Typical AMD contaminant levels 7.
2. Resistivity-conductivity conversion factors 9.
3. Resistivities of selected rocks and minerals 10.
4. NaCl conversion coefficients 15.
5. Ionic conductivity and mobility 18.
6. Summary of EM survey methods 55.
111.
-------
EXECUTIVE SUMMARY
,i
Surface and borehole geophysical methods are an important tool in the investigation and
monitoring of acid mine drainage (AMD) pollution. Geophysical methods can be used in AMD
investigations to:
o map sites of disposal of mining waste;
o map the extent of AMD pollution in aquifers;
o monitor velocity of AMD ground-water pollution;
o delineate depth and lateral extent of waste fills;
o identify potential source areas of AMD;
o locate geologic structures such as faults and formation contacts;
o identify gravel channels within finer grained materials;
o define water table in unconsolidated sediments;
o identify subsurface voids;
o map higher permeability areas within aquifers;
o define the extent of weathering, fracturing and faulting;
o define the extent of protective clay layers;
o map soil conductivity; and
o provide complimentary data for correlating borehole and monitoring well data.
Geophysical methods that can directly measure AMD pollution rely on the resistivity or
conductivity contrast caused by the increase in total dissolved solids associated with the lowering
of pH and the dissolution of sulfide minerals. This increase in soil/rock conductivity is due to a
large increase in specific conductance of ground water within the soil/rock pores. The
relationship between the ground-water geochemistry and the resistivity of the whole soil/rock
mass is complex and non-linear. State-of-the-art application of geophysical methods to
investigations of environmental and hydrogeologic problems requires that site-specific data be
developed to calibrate general empirical relationships. Geophysical techniques best suited to
directly detect subsurface AMD pollution include direct current (D.C.) resistivity and
electromagnetic methods. Induced polarization, self potential, mise-a-la-masse methods may also
be of value in some hydrogeologic settings. Although other geophysical methods do not directly
measure conductivity, they can be of value in AMD investigations in that they provide
complementary information to aid in the subsurface interpretation. These methods include:
-------
seismic, gravity, magnetometer, ground penetrating radar, and various borehole methods.
Field investigations to evaluate the application of D.C. resistivity, electromagnetic, self potential
and magnetometer methods were undertaken at four closed mine sites with known or suspected
AMD pollution. Results of the field investigations are presented in the second volume of this
report. The following conclusions were drawn from an analysis of the survey data collected in
the field investigations.
o Electromagnetic (EM) surface methods were successful in detecting and mapping acidic
ground water in mine waste piles.
o D.C. resistivity methods were successful in developing vertical profiles of acidic mine waste
material that correlated well with electromagnetic survey data and well logs.
o Self potential surveys were successful in detecting acidic ground water flow from mine waste
ponds.
o Magnetometer surveys were proved useful in distinguishing between an increase in
subsurface conductivity due to buried man-made iron or steel objects, and higher specific
conductance from acidic ground water or high conductivity of soils, rock or mine waste.
Included in this report is a review of the literature related to the reported and potential
application of geophysical methods to AMD investigations. The report also briefly discusses:
o The geochemistry of AMD.
o The relationship between ion concentration and specific conductance.
o Empirical relationships that are available to predict the resistivity of soil/rock.
o Formulas for determining the optimum line spacing for geophysical surveys and the
associated probabilities.
VI.
-------
RECOMMENDATIONS
The following are recommended after an extensive review of literature on geophysical
applications to acid mine drainage (AMD) and mapping of fluids with high specific conductance:
o A combination of several geophysical methods such as EM, resistivity, self-potential and
seismic provide a cost-effective method for evaluating potential impacts, defining subsurface
structures, identifying potential flow paths for contaminants, and defining the extent of
ground-water pollution.
o Geophysical surveys should become a standard procedure for preliminary investigation and
monitoring of AMD where subsurface pathways are not readily discernable.
o Geophysical surveys should be used to monitor the migration of AMD plumes between
points of sample collection, such as monitoring wells and springs, to confirm that the best
sample locations have been selected and to help in understanding seasonal changes in
ground-water movement.
o Geophysical instruments are expensive and require technical training to use. Many local
and state agencies faced with AMD do not have the economic resources and staff to
develop an in-house geophysical program. Ready access to geophysical expertise is
desirable. Consideration should be given to developing regional groups of geophysical
experts that can provide professional services and training to local and state agencies.
These regional groups should reside in organizations that have a strong interest in applied
geophysical research. Such organizations might include universities, the U.S. Geological
Survey, some state geological surveys, or technical committees composed of geophysical and
geologic professionals from government and the private sector..
vu.
-------
I. INTRODUCTION
PURPOSE AND SCOPE OF STUDY
Acid mine drainage (AMD) contributes to the pollution of both surface and ground water.
Increasing demand on limited water resources necessitates identification and monitoring of
sources of contamination such as AMD. Traditional methods used for detection, monitoring and
delineation of ground-water contamination rely on monitoring wells. Proper location of
monitoring wells is critical for obtaining accurate data from which to interpret the extent and
concentration of contaminants. A misplaced well can yield erroneous data on the impact of the
contaminants and increase long-term monitoring costs.
AMD is generally associated with an increase in concentration of heavy metals and other ionic
species which increase the specific conductance of both surface and ground waters. This increase
in specific conductance allows mapping of AMD ground-water contamination using geophysical
methods such as resistivity, electromagnetics, and self potential. The conductivity of mine waste
and underlying material is a function of the type of soil and rock, the porosity, and the specific
conductance of the fluids that fill the pores. The specific conductance of the pore fluids is often
the dominant source of the electromagnetic response (McNeill, 1980). Electrical geophysical
methods can be used to map inorganic contaminants, identify direction and extent of contaminant
flow, estimate concentration gradients, develop time-series measurements of plumes, and provide
data for contaminant plume modeling. Although geophysical studies should not completely
replace the use of monitoring wells to collect subsurface hydraulic and water-quality data, they
can provide a low cost alternative to using only monitoring wells for the detection of AMD and
help in selecting locations for monitoring wells.
For this report several tasks were undertaken to evaluate the utility of geophysical techniques in
detection and monitoring of AMD contamination from mine wastes. The tasks were conducted
in three phases:
o Review and summary of literature on geophysical methods that may be useful in evaluating
migration of the high specific conductance contaminants in ground water.
1.
-------
o Selection of several closed mine waste sites in California as candidates for site-specific
geophysical study.
x
o Evaluation of selected sites using electrical resistivity, self potential, and electromagnetic
geophysical surveys to determine the applicability of these techniques in detecting and
evaluating AMD contamination from mine waste. Sites with existing ground-water-quality
data were of particular interest because the data allow a semi-quantitative correlation
between geophysical response and ground water quality.
The geophysical and geochemical criteria identified in the literature review, in conjunction with
certain non-technical criteria such as site access, were used to develop system to rank mine sites
for site-specific investigation.
Reviewed literature focused on geophysical and geochemical conditions that are known to be
associated with AMD and can be detected by surface and borehole geophysical techniques.
These conditions include:
o The presence of conductive minerals, such as pyrite, chalcopyrite, pyrrhotite, hematite, etc.
o The presence of conductive dissolved electrolytes in surface and ground water, such as H+,
Fe2+, Fe3*, SO^, Cu2+, and Zn2+.
o Porosity of soils and interconnection of rock fractures.
o The extent to which pores are filled with water, i.e., moisture content.
ACKNOWLEDGEMENTS
This report was prepared under a grant from the U.S. Environmental Protection Agency through
the Western Governors' Association (Grant X-820497-01-0). The project was administered by
Mr. Stephen Hoffman of the Office of Solid Waste and Emergency Response, U.S.
Environmental Protection Agency. The project was conducted under the guidance of Messrs.
James S. Pompy and Dennis O'Bryant of the California Department of Conservation, Office of
Mine Reclamation (DOC-OMR). Technical review and assistance was provided by Messrs.
Michael Hunerlach, Charles Alpers and F. Peter Haeni of the U.S. Geological Survey, and Dr.
Rodger Chapman of the California Division of Mines and Geology (retired). Field assistance
was provided by Ms. Catherine Gaggini and Mr. Steve Newton-Reed of the DOC-OMR, and
Messrs. Michael Hunerlach, William Hardy and Scott Hamlin of the U.S. Geological Survey,
2.
-------
Water Resources Division, California District in Sacramento. Special thanks go to Mr. William
Croyle of the Central Valley Regional Water Quality Control Board, Ms. Catherine Schoen of
the Tahoe Regional Water Quality Control Board, Mr. Rick Sugarek of Region IX USEPA, and
Mr. Steve Muir of WZI Corporation for their assistance, without which this project would not
have been possible.
-------
II. ACID MINE DRAINAGE (AMD)
GENERAL DISCUSSION OF AMD1
When iron sulfide minerals are exposed to air and water by mining activities, they oxidize and
can produce sulfuric acid. The low pH water in turn leaches metals from other minerals
associated with the sulfide mineralization. The problem of AMD from mining is complicated by
time delays associated with the formation of AMD. Time delays in AMD production are often
due to eventual consumption of gangue minerals with buffering capacity, usually calcite and other
carbonates, as well as to changes in the nature of ore with depth (e.g. increasing sulfide content).
Often, mines with no problem during early periods of mining develop AMD several years or
decades later.
Conclusions regarding AMD reached in a Mine Waste Study commissioned by the State Water
Resources Control Board and conducted by the University of California at Berkeley are
(CSWRCB, 1988):
o AMD is produced by naturally occurring minerals that often are present in great quantities
in mine wastes.
o Once AMD develops, it tends to get worse. Common iron and sulfur oxidizing bacteria,
Thiobacdllus and Ferrobacillus femxxddans, accelerate the process when the pH of the mine
waters falls below a critical value. Thus, the process can be difficult to stop.
o AMD may not develop during mining operations but after closure, when mitigation
measures are difficult to adopt.
GEOCHEMICAL SETTING FOR AMD
AMD is generated from rock containing sulfide minerals, in particular iron sulfides such as pyrite
and marcasite, that are exposed to oxygen by air and water during mining. Stumm and Morgan
(1981) list the following reactions as characteristic of the oxidation of pyrite when exposed to air
and water:
References begin mi page 100.
-------
FeS2(s) + 7/2 02 4- H2O = = > Fe2+ + SO42' + 2 H+ (1)
Fe2+ + 1/4 O2 + H+ = = > Fe3+ + 1/2 H2O (2)
Fe3+ + 3 H2O = = > Fe(OH)3(s) + 3 H+ (3)
FeS2(s) + 14 Fe3+ + 8 H2O = = > 15 Fe2+ + 2 SO42- + 16 H+ (4)
AMD generation is accelerated by acidophilic bacteria, Thiobacillus ferrooxidans and Thiobacillus
thiooxidans, which derive energy from the oxidation of sulfide minerals and Fe2+, accelerating
reaction (2) by 3 to 6 orders of magnitude (CSWRCB, 1988). The production of acid is greatest
at about pH 3.0 due to bacterial activity and diminishes between pH 3.0 and 2.0 due to buffering
reactions that precipitate sulfate, ferric sulfate, and ferric hydroxides (Singer and Stumm, 1970;
CSWRCB, 1988).
The oxidation of sulfides and resulting generation of acid releases heavy metals and sulfosalts
from ore-forming minerals and gangue rock. Heavy metals such as silver (Ag), cadmium (Cd),
cobalt (Co), copper (Cu), mercury (Hg), manganese (Mn), molybdenum (Mo), nickel (Ni), lead
(Pb), zinc (Zn), arsenic, (As), antimony (Sb), and selenium (Se) are commonly associated with
AMD. Table 1 lists typical ranges of AMD contaminant levels from the Appalachian coal region
of the United States (Onysko, 1985). Data compiled as part of a study of mine waste in
California (CSWRCB, 1988) found the concentration of heavy metals rises with a decrease in pH
and, except for copper, zinc, and sulfate, concentration of most other heavy metals and sulfosalt
anions rarely exceeds 100 ppm (CSWRCB, 1988).
GEOCHEMICAL AND GEOPHYSICAL RELATIONSHIPS
General Discussion
The ability of geophysical methods to detect and map an AMD plume in the subsurface is
directly related to the contrast between background and AMD plume conductivity. The degree
of contrast is controlled by the signal noise caused by variability of the hydrogeology, cultural
features, and by limitations of the instruments in sensing plumes at depth. Benson and others
(1985) evaluated the correlation between geophysical signature of high specific conductance
ground-water plumes and the quality of ground water. They evaluated sources of high specific
conductance plumes caused by chloride, sodium, and sulfate that leaked into shallow ground
6.
-------
Table 1
TYPICAL ACID MINE DRAINAGE CONTAMINANT LEVELS2
Parameter
pH
Iron
Fe2+
Fe3+
Total Soluble, as Fe
Sulfate
so,2-
HSCv
Total, as SO42-
Aluminum
Manganese
Acidity to pH 3, as CaCO3
Hydrogen Ion
Bisulfate Ion
Ferric Ion
Aluminum Ion
Ferrous Ion
Humic Acids
Total
Total Dissolved Solids
Suspended Solids
Ionic Strength, molar
Redox Potential
Range of Concentration
8.3
0
0
0
50
0
50
0
0
0
0
0
0
0
0
0
250
5 .
0
-200
- 1.3
- 5,000 mg/L
- 1,000 mg/L
- 6,000 mg/L
- 10,000 mg/L
- 20,000 mg/L
- 20,000 mg/L
- 100 . mg/L
- 100 mg/L
- 2,500 mg/L
- 10,000 mg/L
- 1,000 mg/L
- 500 mg/L
- 5,000 mg/L
- 500 mg/L
- 20,000 mg/1
- 25,000 mg/L
- 5,000 mg/L
- 0.7
- +1,000 mV
' Table after Onyska, 1985
-------
water. D.C. resistivity and electromagnetic (EM34-3 and EM31) methods were compared.
Specific conductance measured in ground-water monitoring wells within the plume and in
background areas were found to have a correlation coefficient ranging from 0.77 to 0.90 at a 95
percent confidence interval with the surface geophysical measurements. Increases in
hydrogeologic complexity, the number of cultural features, and depth of plume all contributed to
a reduction in correlation. Researchers have found that a plume conductivity of at least twice
background is necessary to identify a plume boundary (Greenhouse and Slaine, 1986; Grady and
Haeni, 1984; and Slaine and Greenhouse, 1982 ).
Correlation of electrical geophysical instrument readings and ground water quality can be done
either by using the bulk material conductivity with empirical equations, such as Archie's law, or
by site specific comparison of geophysical readings with water quality data (Benson and others,
1985; and Grady and Haeni, 1984 ). The latter provides a more reliable correlation while the
former can help predict variations in readings.
Electric current can flow through a geologic material in three ways: ohmic, electrolytic, and
dielectric conduction (Telford and others, 1990). Ohmic current occurs in materials such as
metals where free electrons can easily be made to flow. Electrolytic current occurs with ions in
solution and is comparatively slow. Dielectric conduction occurs in poor conductors or insulators
when an external electric field causes electrons to displace slightly, resulting in a temporary
polarization of the material.
Electrical resistivity is a measure of the ease with which electrical current flows through a
substance. Resistivity (p) of a material of cross-sectional area (A), length (L) and resistance (R)
between two faces is:
p = R-A/L
where: R = V/I (Ohm's law)
V = voltage, volts
I = current, amperes
Electrical resistivity is a property of the medium only and is not proportional to the dimensions
of the medium. The units of resistivity in the MKS system (meter-kilogram-second) are ohm-
meters and in the COS system (centimeter-gram-second) ohm-centimeters. Conductivity (a) is
8.
-------
the reciprocal of resistivity (a = 1/p), and is commonly measured in milliSiemens per meter
(mS/m) or rnillimhos per meter (mmhos/m), where 1 Siemen *= 1 mho. Historically, the
conductivity of water, or specific conductance, is given in units of millimhos per meter (mmho/m),
micromhos per centimeter (/imhos/cm). More recently unit of Siemen has replaced the mho.
Table 2 is a list of conversion factors for resistivity to conductivity.
Table 2
RESISirVTIY-CONDUCTTvTTY CONVERSION FACTORS
1 ohm-meter = 100 ohm-centimeter
1 / ohm-meter = 1 mho / meter
1 / ohm = mho
1 mho = 1 Siemen
1 mho / meter = 1000 milliSiemens / meter
1 mho / centimeter = 1 x 106 microSiemens / centimeter
1 / ohm-meter = 1 x 104 microSiemens / centimeter
1 milliSiemen / meter = 10 microSiemens / centimeter
Conductivity of most soil and rock minerals is generally very low because most are electric
insulators. The presence of some minerals such as magnetite, specular hematite, carbon,
graphite, pyrite and pyrrhotite can greatly increase the conductivity of rock and soils (Keller and
Frischknecht, 1966). Table 3 lists resistivity values for selected soil and rock minerals.
Conductivity of electric current through soil and rock is primarily through the pore water
electrolytes. Thus, the volume of pores, the interconnection of pore space and the characteristic
of the pore water electrolyte are all important factors in determining the overall conductivity of
soil or rock. The following are factors that affect conductivity or resistivity of soils and rocks and
are discussed below.
-------
Table 3
RESISTIVITIES OF SELECTED ROCKS A>4D MINERALS3
. Rock/mineral-
Low
Resistivity (Q • m)
High
Average
Arsenopyrite, FeAsS
Qornite, CujFeS4
Chalcocite, Cu,S
Chalcopyrite, CuFeSj
Copper-native, Cu
Coveliite, CuS
Cuprite, Cu,O
Enargitc, GijAsS,
Galena, PbS
Hematite, FejOj
Ilroenite, FeTiO,
Iron-metal, Fe
Magnetite, Fe,O4
Marcasite, FeSj
Pyrite,FeSj
Pyrrhotite, Fe^S,
Sphalerite, ZnS
Sulfur, pure crystals, S
Tetrahedrite, Cu10(Fe,Zn)7Sb4S13
Argillites
Basalt
Diabase
Gabbro
Gneiss
Granite
Limestone
Marble
Quaternary/Tertiary terrestrial sands
Quaternary/Tertiary marine sands
2.0 x 10 5
1.6 x 10*
8.0 x ID'5
3.0 x 10s
1.2 x 10*
3.0 x 10'
1.0 x 10*'
2.0 x 10*
6.8 x 10*
2.1 x 103
1.0 x 10 J
1.5 x 10s
1.0 x Ifr3
6.0 x 10s
2.0 x 10*
2.7 x ID"3
3.0 x 10 '
1.0 x 10*'
1.0 x 10*'
2.0 x 10*'
1.0 x 10*3
6.8 x 10* VO
3.0 x 10*2
5.0 x 10*'
1.0 x 10*2
1.5 x 10*'
1.0 x 10°
1.5 x 10*.'
6.0 x 10 3
1.0 x 10""
83 x 10*'
3.0 x 107
8.0 x 107
5.0 x 10+1
9.0 x 10 '
5.8 x 10 '
4.0 x 10°
4.0 x 10°
1.0 x 10"
1.5 x 10-'
1.2 x 10°
1.6 x 10^
4.0 x 10+<
3.0 x 10*4
SxlO1
13 x I0+7(diy)
5.0 x 10*7
1.0 x 10*'
3.0 x 10+6(w«)
1.0 x 10*'
1.0 x 10+7
2.5 x 10*'(diy)
• 5.0x10*'
1.0 x 10*'
1.9 x 103
9J.x 10s
7.3 x 10^
2.0 x 10 2
1.9 x 102
1.0 x 10*
5.0 x 10*
2.2 X 10 '
7.7 x 1C"5
1.0 x 10*"
1.1 x 10*2
Table after Keller, 1966 and 1989; and Telford and others 1976 and 1990
10.
-------
Table 3 (continued)
RESISTIVITIES OF SELECTED ROCKS AND MINERALS
Rock/mineral
Low
Resistivity (Q • m)
High
Average
Quartizite
Quartz diorite
Sandstone
Shale
Shists, calcareous & mica
Slcarn
Slates
Tuff
Unconsolidated alluvium & sands
Unconsolidated clays
1.0 x 10*'
2.0 x 10*<
1.0 x 100
2.0 x 10+I
2.0 x 10+1
2.5 x 10+2(wet)
6.0 x 10**
2.0 x 10* V«)
1.0 x 10* '
1.0 x 10°
2.0 x 10*'
2.0 x 10* «(wet)
6.4 x 10+8
2.0 x 10°
1.0 x 10*'
2.5 x 10+'(diy)
4.0 X 10*'
1.0 x 10+Vy)
8.0 x 10*2
1.0 x 10*2
2.0 X 10M(»e<)
o Porosity, permeability and heterogeneity
o Electrolyte concentration
o Moisture content
o Temperature
Porosity, Permeability and Heterogeneity
Conductivity of clean sands can be expressed by the empirical formula of Archie (Telford and
others, 1990):
Pe = a •
-------
<|> = porosity, expressed as a fraction of pore volume
S = fraction of pores containing water
a,n,m = constants of regression, with the following ranges,
0.5Sa<2.5
1.3 < m < 2.5
Mazac and others (1987) note that "m", the coefficient of cementation, is somewhat larger than 2
for cemented and well sorted granular rock and somewhat less than 2 for poorly sorted and
poorly cemented granular rock. For unconsolidated, weakly cemented materials with a porosity
that ranges from 20 to 70 percent, a value of 1.3 can be assumed for "m" (McNeill, 1980; and
Keller, 1989). The "a" coefficient varies from slightly less than 1 in rock with intergranular
porosity to slightly more than 1 in rock with only joint porosity and as high as 3.5 in vesicular
tuffaceous rock (Carmichael, 1989).
A commonly used term in formation evaluation is the "formation factor" (FF) which is equal to
Pe/Pw (Telford and others, 1990). Lynch (1962) provided an alternate formula for formation
factor stating that it is a constant of proportionality between the bulk resistivity of the formation
and the resistivity of the pore water. It depends only on the tortuosity and porosity of the rock
and is independent of the water in the pore space as expressed in the following formula:
pe = FF-p
where: FF = (L./L)2 • (1/<|>)
(IVL)2 = tortuosity
L = actual length of a rock block
Le = length of tortuous path through pores in
block, L < L,.
<(» = porosity
For soils, the minerals of sand and silt grains are generally electrically neutral and act as
insulators. Clays act either as insulators or conductors depending on their moisture content and
cation exchange capacity (CEC). The CEC is a measure of the number of cations required to
neutralize the clay particles and is given in milliequivalents adsorbed per 100 grams of soil.
12.
-------
Clays develop from sheet-like or layered silicates which have a negatively charged surface.
Cations such as Ca2+, Mg2"1", H+, K+, Na+, NH4+ are loosely held to clay particle surfaces and are
available for exchange with other more strongly attracted cations, or they may go into solution
when water is present. The small particle size of clays, < 0.002 millimeters in diameter, provides
a very high surface area per unit volume of soil. Thus a large number of cations can be adsorbed
per unit volume and it is these adsorbed cations that affect the soil conductivity.
Although clay particles are poor conductors, a small amount of moisture will create a thin layer
on the particle where adsorbed ions can be dissociated and become available for ionic
conductivity. For shaly sandstones, Lynch (1962) shows that an apparent formation factor FFa
can be estimated using a method proposed by Hill and Milburn (1956). Specifically, FF? can be
related to a formation factor for a fluid with a resistivity of 0.01 ohm-meters (FF0 01) by the
following formula:
FFa = FojM-OOO-p.)1"1*000 ^
where: b ^= - 0.135 • (CEC/<|>) - 0.0055
<|> = volumetric water content, cm3 water/ cm3 soil
pw = resistivity of pore water
Although this formula was derived for formations encountered in oil exploration, it indicates that
CEC has an exponential effect on the conductivity of rock. For soils and rocks where the pore
water is not saline, the conductivity can be strongly influenced by clay content and should always
be considered when interpreting geophysical surveys (McNeill, 1980).
McNeill (1980) proposed the following rules of thumb for determining the change in pore water
concentration needed to affect bulk soil conductivity:
aa = 0.25 • aw
aw = (1/6) • TDS
ca = (1/25) • TDS
where: aa = apparent bulk soil conductivity, mS/m
ow = pore water specific conductance, mS/m
TDS = total dissolved solids, ppm
13.
-------
Field application of geoelectric methods requires consideration of the way electrical properties
are averaged for sections of soil and rock which are generally heterogeneous. Only borehole
geophysical logging provides a method for measuring resistivity of individual layers. Surface
geophysical methods average weathering, depositional layering, and structural discontinuities.
The geologic heterogeneity may also make the earth material electrically anisotropic, that is, the
resistivity may vary with orientation. For example, stratified rocks are generally more conductive
along bedding planes than perpendicular to them. Keller and Frischknecht (1966) point out that
a distinction should be made between the "geoelectric section" and the "geologic section". Their
boundaries may differ because the geoelectric boundary is based on resistivity contrasts which
may not follow a boundary defined on geologic principles such as the fossil record.
Electrolyte Concentration
For electrical current to flow through soil or rock, ions must move through the electrolyte
solution in the pores. The specific conductance of an electrolyte is proportional to both the total
number of ions in solution and their velocity or ionic mobility. The term specific conductance is
used to express the electrical conductivity of a body of unit length and unit cross section at a
specific temperature. Pure water has a very low specific conductance, a few hundred micromhos
per centimeter (/^mhos/cm) or microSiemens/cm (pS/cm) at 25° C (Hem, 1989). For natural
water an approximately linear relationship can be found between the total dissolved solids and
the specific conductance.
An estimate of the relationship between specific conductance and total dissolved solids can be
expressed by the formula:
S = K-A
where: K = specific conductance,/unhos/cm
S ~ total dissolved solids, mg/L
A - regression coefficient
Figure 1, taken from Hem (Fig. 10, p. 67,1989), shows a straight line with a slope of 0.59 visually
fitted to data for waters of the Gila River. A linear regression fit to the lower concentration data
shows that the slope of the line is steeper. A regression line slope ranging from 0.54 and 0.96
14.
-------
can be expected for natural waters with most slopes lying between 0.55 and 0.75. The higher
values are associated with waters that have a high concentration of sulfate.
An alternative method for estimating specific conductance and quality of water is to use the
Schlumberger NaCl curves in Figure 2 developed for fluid-conductivity logs (Alger, 1966; Keys
and MacCary, 1971; and Keys, 1989). To use this method, convert the ionic concentration, in
milligrams per liter, to an equivalent NaCl concentration, then sum to find a total equivalent
NaCl solution. On Figure 2, use the diagonal line equal to the NaCl concentration to find the
temperature of the formation waters and read the conductivity or resistivity of the solution on the
top or bottom horizontal scales, respectively. The ion conversion factors for calculating an
equivalent NaCl solution are given in Table 4 (Keys, 1989; and Lynch, 1962).
For an electrolyte to conduct electric current the solute ions must move through the solvent
(water) to transfer charge. The effectiveness of an ion in transferring charge depends upon its
charge, its size, and the way it interacts with the solvent (Hem, 1989). A measure of the
potential for an ion to transfer charge can be found in its ionic mobility. The ionic mobility
represents the terminal velocity, in centimeters per second, of an ion in a potential gradient of 1
volt per centimeter (Barrow, 1979). Ionic mobility is a function of temperature and
concentration of salts in solution. In a highly-concentrated solution an ion's velocity or ionic
mobility is reduced by the motion of other ions. Changes in temperature also affect the viscosity
of the solution and the ability of ions to move. The effect of temperature changes on ion
mobility is discussed in more detail below. Table 5 lists the ionic mobility for selected ions at low
concentrations and standard temperature of 25° C (Vanysek, 1993).
Table 4
NaCl CONVERSION COEFFICIENTS4
Ion Conversion
Coefficient
Ca2+ 0.95
Mg2* ' 2.00
K+ 1.00
SO4- 0.50
HCO3- 0.27
C032' • 1.26
4 Conversion coefficients from Keys and MacCary, 1971
15.
-------
500 1000 1500 2000 25OO 3000
DISSOLVED SOLIDS. IN MILLIGRAMS PER LITER
3500
Figure 1. Dissolved solids and specific conductance of composites of daily samples
from Gila River, Arizona (from Hem, 1989).
in
«J
in
lit
u
oc
e
3
60
RESISTIVITY — ohm.m«t«rs
5 10 20
50
200
140
20000 10000
5000
2000 1000 500
CONDUCTIVITY — /jmhoi/cm
100
50
Figure 2. Electrically equivalent concentrations of a sodium chloride solution as a
function of resistivity or conductivity and temperature (from Keys and
MacCary, 1971).
16.
-------
An approximation of the specific conductance for dilute solutions of natural water can be
calculated with the following formula (McNeill, 1980; Barrow, '1979; and Keller and
Frischknecht,1966):
a = y- [ClMl + QMj + ...+ CnMn] = 96500 • Z(QMj)
where:
a
Q
specific conductance in mS/m
gram-equivalent weight of the itb ion per cubic meter of
water (gm-eq-wt-nr3). A gram-equivalent weight is the
formula or molecular weight of an ion divided by its
valence.
mobility of the ith ion in square meters per second per volt
(m'-sec-'-V1).
Faraday's constant, 96,500 coulombs of charge per gram
equivalent weight of salt in solution. 1 coulomb =
ampere-sec
For example, one gram of common salt, NaCl, dissolved in 1 cubic meter of pure water (1 mg/L
concentration) would have a specific conductance of 0.22 mS/m = 2.2 /uS/cm (McNeill, 1980).
a = 96500 • {[(23/58)/23] • 5.2 x Hr8 + [(35/58)/35] • 7.9 x Hr8}
a = 0.22 mS/m = 2.2jtS/cm
where: The atomic weight of Na+ = 23, G' = 35, and the molecular weight of NaCl =
58.
An alternative method for relating specific conductance to solution concentration that accounts
for ionic strength is given by the following formula (Laxen, 1977):
L = 1000 • 2 (X,, • Nn)
where:
L
X,,
N
specific conductance, /xS/cm
equivalent conductance of ion n
normality of ion n (millieq-1'1 x 10"3)
17.
-------
Table 5
IONIC CONDUCTIVITY AND MOBILITY5
Ion
Ag
Al
Ba
Be
Ca
Cd
Co
Cr
Cu
Fe
Fe
H
Hg2
Hg
K
Li
Mg
Mn
NH4
N2H5
Na
Ni
Pb
Ra
Rb
Sr
U02
Zn
Au (CN) 2
Au (CN) 4
CN
CNO
Cl
C1O2
C103
C104
F
Fe(CN)6
Fe(CN}6
H2AsO4
HC03
HF2
HS
HS03
H2SbO4
Mno4
MOO4 .
N(CN}2
N03
OCN
OH
P04
SCN
S04
Sb(OH}6
SeCN
Se04
1 +
3 +
2 +
2 +
2 +
2+
2+
3 +
2 +
2+
3 +
1 +
2 +
2+
1 +
1+
2 +
2+
1+
1+
1+
2 +
2 +
2+
1+
2+
2+
2+
1-
1-
1-
1-
1-
1-
1-
1-
1-
4-
3-
1-
1-
1-
1-
1-
1-
1-
1-
1-
1-
1-
1-
3-
1-
2-
1-
1-
2-
lonic-X."
Conductivity
10-4 m:-mho
61.90
61.00
63.60
45.00
59.47
54.00
55.00
67.00
53.60
54.00
68.00
349.65
68.60
63.60
73.48
38.66
53.00
53.40
73.50
59.00
50.08
50.00
71.00
66.80
77.80
59.40
32.00
52.80
50.00
36.00
78.00
64.60
76.31
52.00
64.60
67.30
55.40
110.40
100.90
34.00
44.50
75.00
65.00
50.00
31.00
61.30
74.50
54.50
71.42
64.60
198.00
69.00
66.00
80.00
31.90
64.70
75.70
lonic-M
Mobility
6.42
6.32
6.59
4.66
6.16
.60
.70
.94
.55
.60
.05
7.
4,
5.
7.
5
5
6
5
5
7
36.24
7.11
6.59
.62
.00
5.49
5.53
7.62
6.11
5.19
.18
.36
6.92
8.06
6.16
3.32
5.47
5.18
3.73
8.08
6.65
7.91
5.39
6.69
6.97
5.74
11.44
10.46
3.52
4.61
7.77
6.74
5.18
3.21
6.35
7.72
5.65
7.40
6.69
20.52
7.15
6.84
8.29
3.31
6.71
7.85
mg/L to
Milliequivalents
Coefficient
0.00927
0.11119
0.01456
0.22190
0.04990
0.01779
0.03394
0.05770
0.03147
0.03581
0.05372
0.99216
0.00453
0.00997
0.02558
0.14407
0.08229
0.03640
0.05544
0.03025'
0.04350
0.03407
0.00965
0.00885
0.01170
0.02283
0.00741
0.03059
0.00402
0.00332
0.03844
0.02380
0.02821
0.01483
0.01198
0.01006
0.05264
0.01887
0.01415
0.00710
0.01639
0.02564
0.03024
0.01234
0.00533
0.00841
0.00625
0.01514
0.01613
0.02380
0.05880
0.03159
0.01722
0.02082
0.00447
0.00953
0.01310
44.6
217.6
119.1
102.0
115.3
110.3
111.2
229.2
109.9
110.3
231.7
110.7
123.7
119.1
47.2
39.2
109.2
109.8
47.2
43.9
41.8
106.6
126.0
122.1
48.2
115.3
90.1
109.2
41.8
38.6
48.3
45.2
47.9
42.3
45.2
45.8
43.1
527.5
299.8
38.1
40.6
47.6
45.3
41.8
37.4
44.4
47.5
42.9
46.7
45.2
75.9
233.8
45.5
134.2
37.7
45.2
130.4
5 Table modified after Vanysek, 1993; and Laxen, 1977. Values given for standard temperature of 25'C.
18.
-------
The concentration in milligrams per liter can be converted to milliequivalents using conversion
factors listed in Table 5. The equivalent conductance for each ion is calculated using the formula
(Laxen, 1977):
X. = Xn° + [x]
where: X,,0 = equivalent conductance for ion n in an infinite dilute solution,
cm2/(equivalent • Q) = 10"4 m2 • mho
[x] = conversion coefficient for ion n
I = ionic strength
Values of K° are listed in Table 5. Values of coefficient [x] incorporates ionic charge and are
listed in Table 5. For a detailed discussion of the derivation of coefficient [x] see Laxen (1977).
For a dilute solution, ionic strength can be calculated from the normality using the formula
(Laxen, 1977):
I = 0.5 2 (Nn • zn)
where: Nn = normality of ion n
zn = valence of ion n
Using the above formulas, a computed value for the NaCl solution specific conductance of
approximately 2.2 jiS/cm is obtained. Applying this value to the regression formula given on
page 15, a regression coefficient of 0.46 (1/2.2) is found. This coefficient is slightly less than that
found for natural waters which usually contain some divalent ions.
Moisture Content
Rhoades and others (1976) evaluated the relationship between soil electrical conductivity (EC),
soil water content (6), soil salinity, and other pertinent soil properties. They developed a two
parallel conductor model for bulk soil electrical conductivity (ECa).. The two conductors are due
to a bulk liquid-phase conductivity which depends linearly on the electrical conductivity of the
soil water (EQ,), and a bulk surface conductivity (ECS) from exchangeable ions at the solid-liquid
interface. This relationships can be expressed in the formula:
19.
-------
ECa = EC, • 6 • T + EC,
where: 6 = volumetric water content
v T — transmission coefficient which accounts for tortuosity of
electrical current flow
An empirical formula for T is given by:
T = a-6 + b
where: a and b are regression constants taken from a plot of
{(ECa - EC,)/ECw}/6 versus 6
Rhoades and others (1976) found the surface conductivity greater for finer-textured soils. When
water content was less than a threshold value (6, = -b/a), the conductivity of the soil due to the
pore water electrolyte was zero. Their experiment in four soils found 9, to range from 0.05 to
0.12. Rhoades and others (1976) concluded that it may be possible to estimate EC* and
coefficients a and b based on soil texture and mineralogy. Thus pore water electrical conductivity
(EC*) could be determined by measuring the bulk electrical conductivity (ECa) and the
volumetric water content (6).
Keller and Frischknecht (1966) discuss the resistivity of rocks and note that pores may be filled
with electrolytes (water), gases (air), or non-conductive fluids (oil). They give the following
formula for the relationship between the bulk resistivity and the degree of saturation:
P/Pioo - S,-1 ; Sw>Swe
where: p = bulk resistivity of partially saturated rock
p100 = bulk resistivity of fully saturated rock
nj = experimentally derived parameter « 2
S, = fraction of pore volume filled with electrolyte
Jv = critical water content
This relationship holds provided the water content is above a critical value (S^) based on texture.
S^c is defined as the point where a continuous film of water still covers the rock surfaces. S^
varies from approximately 25 percent for sandstone to 80 percent for igneous rocks.
20.
-------
When the moisture content drops below the critical saturation, the formula for relating resistivity
to degree of saturation is:
P/Pioo = a-Sw"2 ; SW
-------
III. APPLICATION OF GEOPHYSICAL METHODS
TO AMD INVESTIGATIONS
GENERAL DISCUSSION
The following sections present reviews of geophysical methods as they relate to investigation of
AMD pollution. Each of the sections discuss the basic geophysical theory, the historic and
potential application to AMD investigations, and field procedures. More detailed discussion is
provided for those methods that have direct applicability to AMD problems: D.C. resistivity,
mise-a-la-masse, induced polarization, electromagnetics, and self potential. Methods that do not
have a direct relationship to AMD pollution (seismic, gravity, magnetometer, ground penetrating
radar) are discussed briefly and references are provided. The final section on borehole
geophysical methods is not intended as a detailed review but as a source of references for more
detailed information.
The next section is about optimum sample spacing and the probability of finding an object, given
the sample spacing and the size of the object. The formulas are primarily for a two dimensional
space, that is, the object to be found is assumed to lie on the plane of the sampling grid. It
should be recognized that the sampling space of geophysical methods is really three dimensional
and complex. The ability of a geophysical method to detect a buried object is related to the
sensitivity of the instrument, the basic physics of the method, the geometry of the target, the
depth of the target, and the location of the target with respect to the sampling points. Thus
selection of the appropriate geophysical method(s) for an investigation should be based on
whether the instrument can measure to the target depth; then the issue of grid spacing should be
addressed. Careful consideration of grid spacing and probabilities can provide insight into the
density of sampling that is necessary to find a specific size object.
23.
-------
OPTIMUM SAMPLING IN GEOPHYSICAL SURVEYS6
k
Geophysical surveys are generally conducted along a line or grid in order to intersect features of
interest. The selection of the proper sampling density is critical to finding the object of interest
at minimal cost. The "optimum" distance between survey lines should be such that the
geophysical anomaly is defined. However, the concept of "optimum" should also be expressed in
terms of the probability of detecting a geophysical anomaly, since "optimum11 implies
maximization or minimization with respect to a subjective benefit. The "optimum11 survey grid
would always be the one that has a 100 percent chance of finding the object of interest at the
least cost.
The issue of optimum point or line spacing has been generally addressed by Parasnis (1986) and
in more detail by Agocs (1955), as well as Kendal and Moran (1963). For geologic structures
that are uniform over a long distance, the spacing of geophysical survey lines can be kept large
provided the individual observation points along the line are relatively close. As a general rule,
geophysical surveys can not be expected to yield information about features whose depth is much
smaller than the distance between observations (Parasnis, 1986).
The following formulas can be used to find the probability of intersecting an anomaly (Agocs,
1955):
o For a circular anomaly of diameter D, that is less than the line spacing S, the probability
of a line crossing the anomaly would be:
P = D/S
o For a randomly distributed, elongated anomaly of length L, where the line spacing S is
greater than L, the probability of crossing the anomaly would be:
P - (2-L)/(7t-S)
24.
6References begin on page 100.
-------
o For a randomly distributed anomaly having a length L, that is greater than the line
spacing S, the probability of crossing the anomaly would be:
P = [2 • L / (TC • S)] • {1 - [(1 - S2) / L2]1*} + (2 / TC) • arccos(S / L)
or
P = {[(2 • L) / (TC • S)] • [1 - sin(00)]} + {(2 • 60) / TC}
where: S/L = cos(60)
60 = degrees in radians
o For a randomly distributed rectangular anomaly of length L and width W, whose diagonal
is less than the line spacing S, the probability of crossing the anomaly would be:
P = 2-(L + W)/(7t-S)
o For irregular shaped anomaly of perimeter A, the probability of crossing the anomaly
would be:
P = A/(rt-S)
o For a grid spacing of S and T, where T > S, and where an elongated anomaly of length
L, L < S, the probability of crossing the anomaly would be:
P = {2-L-(S + T)-L2}/{7t-S-T}
o For a circular anomaly of diameter D where D is smaller than the side of the grid, the
probability of crossing a randomly distributed anomaly would be:
P - D-{(S + T)-(rc-D)}/{S-T}
25.
-------
D.C. RESISTIVITY GEOPHYSICAL METHODS7
GENERAL DISCUSSION
Basic Principles
Resistivity using direct current is one of the oldest surface geophysical methods. Conrad
Schlumberger first applied D.C. resistivity in 1912 (Koefoed, 1979). The D.C. resistivity method
investigates changes in subsurface layering geoelectric properties by passing direct current or low
frequency alternating current through electrodes placed in the earth and then measuring the drop
in potential (voltage) across another set of electrodes.
When resistivity measurements are made in an earth that is a homogeneous, isotropic, semi-
infinite half-space, the value measured is the true resistivity of the earth. However, the earth is
made of layers of materials that vary laterally and vertically in resistivity. Thus, the values of
resistivity measured with resistivity methods are apparent and not true. The measured resistivity
is a function of electrode geometry, electrode spacing, the true resistivity and thickness of each
layer, layer dip, and lateral variations within layers.
The resistivity of a homogeneous, isotropic material between two electrodes can be found using
the formula:
where:
P
A
L
R
AV
^References begin on page 104.
26.
p = (A/L)-R
electrical resistivity, ii-m
cross-sectional area, m2
length of current flow path, m
AV/I, Ohm's law
difference in voltage potential
across two electrodes, volts
electrical current, amperes
-------
Geoelectric properties of a layer (i) can be described by resistivity (p;) and thickness (h;). Using
these two parameters, other geoelectric properties can be defined (Keller and Frischknecht, 1966;
Ward, 1990; and Zohdy and others, 1974).
For a column of homogeneous earth material with a unit cross-sectional area made of layers of
differing resistivity and thicknesses, a longitudinal unit conductance (S;) for layer i taken parallel
to the layering, and a transverse unit resistance (T;) taken normal to the layering can be defined.
Geoelectric parameters T; and S; are also known as "Dar Zarrouk" parameters and are given by
the following formulas:
- h • Pi
Electrical properties of a geoelectric layer / can also be described by the longitudinal resistivity
along bedding planes (pL) and the transverse resistivity perpendicular to bedding planes (pr).
These properties are defined by the following formulas:
PL =
Pr -
The total longitudinal conductance (Sj) and transverse resistance (TT) of a column of
geoelectrically different layers can be calculated by summing the unit longitudinal conductances
and transverse resistances using the following formulas:
ST = 2(hi/Pi)
T =
21.
-------
For current flowing perpendicular to the layers, the average transverse resistivity (pTa) can be
found by dividing the total transverse resistance by the total ccflumn thickness using the formula:
oTa =
where: 2(p; • h;) = total transverse resistance of i layers
Zh; = total column thickness of i layers
For current flowing parallel to the layers, the average longitudinal resistivity (p^) can be found
by dividing the total column thickness by the total longitudinal conductance using he using the
formula:
where: Z (h; / pj) = total longitudinal conductances of i layers
Z h; = total column thickness of / layers
Longitudinal resistivity is always smaller than transverse resistivity with the difference being a
measure of the geoelectrical anisotropy (Keller and Frischknecht, 1966). A coefficient of
anisotropy can be defined as the square root of the ratio of the total resistivity measured in the
two principle directions, along and perpendicular to layering and is given by the formula:
An average or mean square resistivity of an anisotropic block can be given as the square root of
the product of the total horizontal and vertical resistivities and is given by the formula:
Pm = (Pr' PL)W
Equivalence and Suppression
When interpreting multilayer soundings, T and S are sometimes all that can be determined
uniquely because various combinations of h; and p; can give the same or equivalent sounding
28.
-------
curve. This is the problem of "equivalence" and is important when interpreting soundings
(Maillet, 1941; Parasnis, 1986; Zohdy and others, 1974; and Telford and others, 1990). As an
example, a thin resistive layer is characterized by T = h; • p;, whereas a thin conductive layer is
characterized by S = h; / p;. Although T and S can be found, hi and PJ cannot. Thus, it is
impossible to distinguish between two highly resistive beds of different thickness and resistivity if
the product h; • p; is the same, or between two highly conductive beds if the ratio of h; / ft is the
same (Telford and others, 1990). Also, two or more layers can be combined to provide an
equivalent sounding curve. Other methods of geophysical survey or actual subsurface layering
information are needed to confine the solution.
Another problem with interpretation of D.C. resistivity surveys is that of suppression. When the
thickness of a layer is small compared to its depth, or when the thickness is small compared to
the layers above and below, the influence of the layer on the apparent resistivity measured at the
surface is small. The presence of the layer is unknown or suppressed, except for layers of
extremely high or extremely low resistivity.
Many computer programs that model resistivity sounding curves for a multilayer earth can also
produce a correlation matrix that indicates sensitivity of the relationship between h; and pj. Ward
(1990) states that correlation coefficients must be greater than 0.72 to be statistically significant.
Survey Methods
Electrical resistivity surveys can be performed in three general configurations: vertical sounding,
horizontal profiling, and a combination of the two. Two other methods, mise-a-la-masse and
induced polarization, will be discussed separately.
Vertical sounding (VES) is a process by which the separation between the current and potential
electrodes is progressively increased over a fixed central point. This causes the array to measure
the apparent resistivity at progressively deeper depths. VES is used to investigate vertical
changes in subsurface layering and produces a geoelectrical cross section.
Horizontal profiling is a method for measuring the lateral variations in resistivity by progressing
the survey along a linear traverse using a constant electrode spacing. A constant spacing implies
29.
-------
a constant depth of investigation. Horizontal profiling is primarily used to locate geologic
structures sjuch as buried channels, faults, dikes, and anomalou's 2-D and 3-D bodies.
The combined method repeats the horizontal profiling method at wider electrode spacings to
obtain a series of profiles that can be presented as a geoelectric pseudo-cross-section.
Array Electrode Geometries
The most common D.C. resistivity methods use four electrodes placed in a straight line with
various geometries. One pair of electrodes induces current into the subsurface, and the other
pair measures the difference in electrical potential or voltage. When two current electrodes are
placed into the earth's surface and an external D.C. current (or with more modem instruments a
low frequency alternating current) is applied, electrical current flows through the earth from one
electrode to the other as shown in Figure 3a for a homogeneous, isotropic earth model. The
lines of current flow are perpendicular to the lines of drop in electrical potential, or the
equipotential lines. The ideal current lines shown in Figure 3a are marked with the percentage
of current carried by each line. The drop in potential between successive equipotential lines is
constant.
The electrode configurations commonly used in D.C. resistivity studies (Zohdy and others, 1974)
are:
1. Wenner
2. Schlumberger
3. Dipole-Dipole
4. Lee-partitioning
The Wenner array uses four electrodes placed in a straight line and spaced at equal intervals (a)
as shown in Figures 3b and 4a. The apparent resistivity (pw) is a function of the distance between
electrodes and is given by the formula in Figure 4a.
The Schlumberger array uses four electrodes along a straight line but with an irregular spacing
where the distance AB between the current electrodes is equal to or greater than 5 times the
distance MN between the potential electrodes as shown in Figure 4b. The apparent resistivity is
30.
-------
SURFACE
Figure 3a.
Figure 3b.
Potential and current distribution in a vertical plane along the line of electrodes.
Current lines of flow each carry one-tenth of the total current. The potential drop
between successive equipotential lines is constant (from van Nostrand and Cook,
1966).
Current
Source
.Current Meter
Surface
Current
Voltage
Wenner array D.C. resistivity equipotential and current flow lines. Current is
induces in outer set of electrodes, Q and Q, and voltage drop is measured across
inner set of electrodes, Pj and P2 (from USEPA, 1986).
-------
a function of the distance AB/2. In practice, MN is kept constant and AB/2 is expanded to
obtain deeper soundings. As the distance AB/2 widens, the voltage drop across MN is reduced.
At some point, it is necessary to increase the MN distance to obtain deeper soundings. The
apparent resistivity (pB) is given by the formula in Figure 4b.
The Lee-partitioning array is similar to the Wenner array except that an additional electrode (O) is
placed midway between the M and N potential electrodes. Potential differences are measured
between the MO and NO. The formula for calculating apparent resistivity (p,) is given in Figure 4c.
The dipole-dipole array has several configurations but the most common are the axial and
equatorial as shown in Figure 4d and e, respectively (Parasnis, 1986; and Zohdy and others,
1974). The dipole-dipole array differs from the others in that the current electrodes are
separated from the voltage electrodes. The separation between each electrode within a pair is
often kept the same and is significantly smaller than the distance (r) between the current and
potential electrodes as shown in Figure 4d. Dipole-dipole has an advantage over Schlumberger,
Wenner and Lee-partition because shorter AB and MN spacings are needed for deep
penetration. Disadvantages are that the dipole-dipole is harder to interpret and local lateral
variations are harder to detect. An alternative to the dipole-dipole method is to enlarge the
separation at one or both pairs of electrodes so that they act as bipoles creating a bipole-dipole
or bipole-bipole array. Figure 4e shows an equatorial bipole-dipole array and formulas for
calculating the apparent resistivity for the axial (pa) and equatorial (pe) arrays.
Depth of Investigation
The Wenner and Schlumberger methods are used most often in environmental and ground-water
investigations because they are the easiest to implement and interpret. Interpretation of
resistivity measurements assumes that the earth is made of a sequence of geoelectrically distinct
layers of finite thicknesses. Contacts between layers are assumed to be horizontal to the array
spacing.
When selecting the type of array to use for a survey, it is important to note that the actual depth
of investigation of each type of array is governed by a number of factors including signal-to-noise
ratio, sensitivity to surficial inhomogeneities, sensitivity to bedrock topography, sensitivity to dip
32.
-------
M N
a.
• a »4-« a
WENNER ELECTRODE ARRAY
Pw =
MM
b. h AB/2 4« AB/2-
SCHLUMBERGER ELECTRODE ARRAY
(AB/2)8—(MN/2)3
Hs = ir
MN
M O N
B
•
c.
LEE—PARTITIONING ELECTRODE ARRAY
H
• i • • . •
A Q B M ° N
AXIAL OR POLAR
P.
(AB)(MN)
Pc =
Figure 4.
EQUATORIAL
Electrode configurations for D.C. resistivity arrays with formulas for interpreting
apparent resistivity (after Zohdy and others, 1974).
33V
-------
of layers, and others (Ward, 1990).
•
There are a number of investigations of the depth to which a surface D.C. resistivity survey can
detect a buried target or differentiate layers (Evjen, 1938; Muscat, 1941; Roy and Apparao, 1971;
Roy, 1972; Barker, 1989; and Apparao and others, 1992). One of the problems in comparing
these studies is that the definition of the depth of investigation or depth of detection is not
consistent. The depth of investigation for resistivity methods can be defined as the depth to or
below which one-half of the total current penetrates (Eyjen, 1938). Evjen found this depth to be
approximately equal to half the current electrode spacing for a homogeneous earth. An alternate
definition (Roy and Apparao, 1971) of the depth of investigation characteristic is the point at
which a thin horizontal layer contributes the maximum amount of the total signal at the surface.
Roy and Apparao (1971) and Roy (1972) found for four methods the following values for the
depth of investigation based on a distance of L between the extreme electrodes:
Equatorial dipole-dipole 0.125-L
Polar dipole-dipole 0.195-L
Schlumberger 0.125-L
Wenner 0.110-L
Barker (1989) reviewed the issue of the depth of investigation and defined a normalized depth of
investigation characteristic curve. Barker (1989) found the depth of investigation to be 0.170-L
for the Wenner array, 0.190-L for the Schlumberger, and 0.250-L for the dipole-dipole. Where L
is the distance between extreme electrodes.
Apparao and others (1992) defined the depth of detection of an electrode array as the depth
below which a target cannot be detected assuming a minimal anomaly of 10 percent. This
minimal anomaly is based in part on the findings of van Nostrand (1953) that the limiting depth
of detection for an infinitely conducting buried spherical target is approximately equal to the
radius of the sphere for the Wenner array. The depth of detection is not easily predicted and is
dependent upon the shape, size, and conductivity contrast of the target, and orientation of the
sounding array relative to the target.
Ward (1990) presents a detailed discussion of the factors influencing the depth of investigation
and sensitivity of each array. In general, the depth of investigation for the Wenner,
34.
-------
Schlumberger and Lee-partition methods is predominantly controlled by the distance between
current electrodes. Thus equal current electrode spacing produces nearly equal depths of
investigation with the Schlumberger array having a slightly greater penetrating depth and
resolving power in VES surveys than the Wenner for the same current electrode (AB) spacing.
For horizontal profiling they are approximately equal and the dipole-dipole survey is considered
less sensitive (Ward, 1990). Barker (1989) notes that for all methods a low resistivity layer at the
surface reduces the depth of investigation.
Today a more practical approach for evaluating the depth of investigation is to conduct several
forward modeling computer simulations to evaluate the sensitivity of the method in detecting the
assumed target(s).
Comparison of Arrays
Each D.C. resistivity method has advantages and disadvantages over the others. Zohdy and
others (1974), Pennington (1985), and Ward (1990) provide a detailed discussion of the pros and
cons of various resistivity methods. The following is a list of items that can be used to compare
the four methods:
o Most D.C. resistivity methods assume the subsurface layers are horizontal and
geoelectrically homogeneous. This condition is almost never met, and small lateral
variations in near-surface resistivity cause noise and relative error that affects Wenner,
Schlumberger and Lee-partition methods more than the dipole-dipole method. However,
because the Schlumberger array maintains a constant spacing for the potential electrodes
for several current electrode spacings, the error caused by lateral change is smaller and
more easily detected than with the Wenner array. As long as the lateral extent of the
near-surface inhomogeneity is small compared to the separation of the current electrodes,
the relative error produced by the Schlumberger array will be the same for all
measurements with the same potential electrode spacing.
o Dipole-dipole arrays are generally applied to deep investigations. The separation of the
current and potential electrodes allows for shorter cables than the other methods for a
particular depth of investigation. However, the potential difference measured with the
dipole-dipole is smaller than with the others and requires more current input and a more
sensitive instrument for measuring the voltage potential.
35.
-------
o The potential electrode spacing (MN) for the Schlumberger array is always kept, small
compared to the current electrode spacing (AB) which should be greater than or equal to
at teast 5 times the MN spacing. With the Wenner array, the current electrode spacing is
always equal to 3 times the potential electrode spacing.
o Schlumberger MN spacing is changed occasionally, as the signal becomes weak, while the
AB spacing is changed between each measurement. With the Wenner and Lee-partition
arrays MN is always changed along with the AB electrodes for each measurement.
o The AB electrode spacing for the Schlumberger, Wenner and Lee-partition arrays should
be at least 3 times and preferably 5 to 10 times the maximum depth of interest.
o The smallest electrode spacing for the Schlumberger, Wenner and Lee-partition arrays
should.be less than one-half the minimum depth at which a change in material is
expected.
o Spacing of electrodes should be logarithmic. That is, data should be taken at roughly
equal spacings as plotted along a log scale of AB or AB/2 spacing.
o Dipole-dipole can provide more details on the dip of layering than other methods.
o Stray currents in industrial areas and telluric currents measured with long array spreads
affect the Schlumberger array less than Wenner and Lee-partition arrays.
o Drift or unstable potential measurements from electrodes in the ground are less with a
Schlumberger array since the potential electrodes tend to stabilize after 5 to 10 minutes.
o Current leakage from cables is less of a problem with the dipole-dipole array. The
problem of inductive coupling is minimized.
o Special methods of interpretation are needed for dipole-dipole.
o It is possible to get an indication of the lateral change in the subsurface with the Lee-
partition array, but data reduction is not simple.
o The Schlumberger sounding curve is discontinuous whenever the MN spacing is enlarged.
The curve is shifted upward or downward to smooth the sounding plot. The discontinuity
is an indication of local inhomogeneities near the MN electrodes.
Interpretation of Resistivity Data
Today, VES is interpreted by using a numerical model to find a best-fit match of the data to an
ideal geoelectric VES curve (Ward, 1990; Zohdy and others, 1974). Horizontal profiling is
generally interpreted qualitatively by plotting the field apparent resistivity values as either a linear
trend plotted on an X-Y graph, or by contouring a map of apparent resistivity at a specific
36.
-------
electrode spacing. The contour map presents a two-dimensional picture of the apparent
resistivity at a constant a-spacing but at an apparent depth.
The combined method of horizontal profiling at different electrode spacings usually presents the
data as a contoured geoelectric cross section or pseudo-section (Ward, 1990; Hallof, 1992). The
resistivity contours are pseudo-contours since the field apparent resistivity data are arbitrarily
assigned to a point below the center of the array at a depth often set equal to one-half the
current electrode spacing. Other methods of cross section interpretation use numerical computer
models to estimate the distribution, resistivity and thickness of layers (Hohmann, 1982).
Interpretation of D.C. resistivity data can be a complex task when the subsurface is not ideal, that
is, not a homogeneous, horizontally-layered and laterally extensive half-space with geometrically-
simple-shaped, homogeneous resistivity targets. Prior to the availability of computers,
interpretation of VES data was by matching field data to Master Curves for 2, 3, 4 or 5 layer
models developed based on various assumptions about the contrast in layer resistivity (Mooney
and Wetzel, 1954; Flathe, 1963; Orellana and Mooney, 1966; Orellana and Mooney, 1970; Larzeg,
1973; and Koefoed, 1979). The use of master curves is limited because the infinite combinations
of resistivity and layer thickness could not possibly be tabulated. Today computer simulations
have replaced curve matching.
The shape of the apparent resistivity curve is influenced by the electrode spacing, the width of
the discontinuity, the angle between the profile line and the strike of the discontinuity, and the
resistivity of the juxtaposed rock units. There can be abrupt changes in the slope of the apparent
resistivity curve where the electrodes of a horizontal profile survey cross a buried structure. A
structure such as a fault zone can either increase or decrease conductivity depending on the
nature of the surrounding rock and the material that fills the fault zone.
One of the basic assumptions for D.C. resistivity surveys is that they are conducted across a
homogeneous, horizontal ground. When variations in slope are greater that 10 degrees or highly
irregular, there are noticeable effects that should be corrected (Fox and others, 1980; Telford and
others, 1990; and Ward, 1990). Impacts of topography are caused by variations in depth to
layering, and moisture content as well as concentration of current flux in valleys and divergence
of current beneath hills (Fox and others, 1980; Holcomb and Jiracek, 1984; and Ward, 1990).
37.
-------
Any of the electrode array configurations discussed above can be used for mapping lateral
geologic changes, but the profiles of each array differ considerably (Telford and others, 1990).
The variation in array profiles is more dramatic with a wide zone of anomalous resistivity, such as
a fault zone or dike, than with a contact between two rock types. Telford and others (1990)
demonstrate that for zones of anomalous resistivity, the half Schlumberger array best reproduces
the shape of the anomalous zone.
The Wenner and Schlumberger resistivity methods are' best suited for delineating horizontal
layers and vertical contacts, and are less useful for bodies of irregular shape (Ward, 1990; and
Telford and others, 1990). These resistivity methods are not particularity sensitive to 3-D
anomalies unless the depth of the anomaly is less than the radius of the anomaly. For the
Schlumberger array, a maximum response of 12 percent contrast occurs when the depth to the
center of a buried sphere is equal to the sphere's diameter. Hallof (1992) indicates that for
buried spherical shaped bodies the dipole-dipole array provides the largest anomaly.
Numerous studies have been conducted to determine the response of surface D.C. resistivity to
various buried simple-geometric-shaped objects (van Nostrand, 1953; Vozoff, 1958; Unz, 1963;
Al-Chalabi, 1969; Zohdy, 1969b and 1970b; Coggon, 1971; Stefanescu and Stefanescu, 1974;
Koefoed, 1976a and 1976b; Dey and Morrison, 1979; Speigel and others, 1980; Pridmore and
others, 1981; Hohmann, 1982; Mundry, 1984; and Tripp and others, 1984; and Griffiths and
Barker, 1993).
Interpretation of resistivity soundings and profiles can now be readily done using forward and/or
inverse modeling on personal computers (Koefoed, 1979; Mooney, 1980; Interpex, 1988; Bankey
and Anderson, 1989; Orndorff and others, 1989; Zohdy and Bisdorf, 1989; and Bisdorf and
Zohdy, 1990). However, the interpretation of data is still limited by the problems of equivalence
and suppression as discussed above.
38.
-------
USE OF D.C. RESISTIVITY IN AMD INVESTIGATIONS
*
*
General Discussion
Reports on the use of conventional D.C. resistivity for investigation of AMD pollution include:
Merkel (1972), Greenfield and Stoyer (1976), Ladwig (1982), Kehew and Groenewold (1983),
Dave and others (1986), Ebraheem and others (1990), and Benson (1993). These reports
document the application of D.C. resistivity to investigating subsurface distribution of mine
wastes, identifying possible high mineralization areas within the waste, identifying areas of
ground-water pollution and subsurface discharge, and development of empirical relationships
between apparent resistivity and ground-water quality (total dissolved solids and specific
conductance). The investigation methods used were VES and horizontal profiling methods with
the Wenner and Schlumberger arrays.
D.C. resistivity has been used by geologists for many years in the exploration of mineral, ground-
water and petroleum resources. Geophysical textbooks and publications on the general
application of D.C. resistivity include: Maillet (1947), Keller and Frischknecht (1966), Kunetz
(1966), van Nostrand and Cook (1966), Morley (1967), Soil Test (1968), Bhattacharyya and Patra
(1968), Parasnis (1973 and 1986), Koefoed (1979), Telford and others (1976 and 1990), Hallof
(1992), and Keller (1993).
Publications that address the general application of surface D.C. resistivity to ground-water,
environmental and geotechnical investigations include: Flathe (1955), Breusse (1963), Krulc and
Mladenovic (1969), Zohdy and others (1974), Kelly (1976), USEPA (1978), Mooney (1980),
Griffiths and King (1981), Bruehl (1983), Dobecki and Romig (1985), Bisdorf (1985), Kelly and
others (1988), Ward (1990), Buselli and others (1992), and Henderson (1992).
Although the number of reports on D.C. resistivity investigations of AMD pollution are limited,
the literature has numerous D.C. resistivity studies on ground-water pollution. The results of
these studies can be readily applied to investigation of AMD since they deal with geologic,
geochemical, and hydrogeologic conditions often found at mine sites. Discussion of D.C.
resistivity investigations as applied to AMD is divided into the following general categories:
39.
-------
o geologic structure and stratigraphy
o ground-water protection zones
o aquifer properties and ground-water quality
o fracture systems
o landfills and waste impoundments
o open and filled voids
o long-term monitoring
Geologic Structure and Stratigraphy
Studies of the application of D.C. resistivity to investigation of geologic stratigraphy and
structures are numerous and include texts and reports by Logn (1954), van Nostrand and Cook
(1966), Lennox and Carlson (1967a and 1967b), Zohdy (1970), Telford and others (1976,1990),
Koefoed (1979), Verma (1979), Ayers (1989), Barker (1990); Alfano (1993), and Kelley and
Mares (1993). Geologic structures of particular interest in AMD investigations include faults,
fracture systems, rapid lateral and vertical changes in stratigraphy, boundaries of buried waste
piles, .buried alluvial channels, buried tunnels and mine workings, open sink holes or cavities, and
filled cavities.
Application of D.C. resistivity to investigation of near vertical discontinuities is discussed in detail
by van Nostrand and Cook (1966). Investigation of lateral discontinuities is best done using
horizontal profiling, provided the depth of the target is identified. Selection of the proper
horizontal array should be done by evaluating existing subsurface data and conducting several
preliminary VES surveys.
•
Direct current resistivity has been used in numerous studies to investigate aquifer properties, the
extent of ground-water resources, and mapping of the depth and lateral extent of the fresh-water
salt-water interface. These studies include: Hallenback (1953), Breusse (1963), van Dam and
Meulenkamp (1967), Flathe (1967 and 1976), Krulc and Mladenovic (1969), Zohdy (1969a),
Merkel and Kaminski (1972), Zohdy and Jackson (1973), Frohlich (1973 and 1974), van Dam
(1976), Topfer (1976), Worthington and Griffiths (1976), Worthington (1977), van Overmeeren
(1981), Urish (1983), Underwood and other (1984), Park and others (1984), Mark and others
(1986), Owen and others (1991), and Briz-Kishore (1992).
40.
-------
Ground-Water Protection Zones
\
Several studies have been, conducted to evaluate the use of surface resistivity in delineating
ground-water protection zones around production wells (Mazac and others, 1987; Kalinski and
others, 1993a). These studies rely on the fact that the apparent resistivity on the surface can be
correlated with the thickness of a protective clay or silt layer once sufficient VES surveys have
been conducted. Kalinski and others (1993b) discuss the use of D.C. resistivity soundings and
profiling to empirically estimate the vertical travel time of ground water through a protective clay
layer. Their study found that the vertical travel time can be directly proportional to the square of
the longitudinal conductance (S2) of the protective clay layer when the layer is more conductive
than the underlying aquifer, a common occurrence for fresh-water sandy aquifers overlain by a
clay layer. Mazac and others (1987) discussed the development of ground-water protection zone
using various geophysical methods including D.C. resistivity.
Aquifer Properties and Ground-Water Quality
One of the more interesting applications of D.C. resistivity is its use in estimating physical and
chemical properties of aquifers. Studies have demonstrated that empirical relationships can be
developed between geoelectrical parameters such as apparent resistivity, transverse resistivity,
longitudinal conductance, and apparent formation factor, and between aquifer properties such as
hydraulic conductivity, transmissivity, effective porosity, specific capacity, salinity, and total
dissolved solids (Page, 1968; Worthington, 1975 and 1976; Griffiths, 1976; Henriet, 1976; Kelly,
1977; Mazac and others, 1979,1985,1987,1990, and 1992; Urish, 1981; Kosinski and Kelly, 1981;
Niwas and Singhal, 1981; Kelly and Reiter, 1984; Ponzini and others, 1984; Ringstad and
Bugenig, 1984; Taylor and Cherkauer, 1984; Frohlich and Kelly, 1985; Bardossy and others, 1986;
Huntley, 1986; Ahmed and others, 1988; Mbonu and others, 1991; Ritzi and Andolsek, 1992; and
White (1994).
Typically correlations are developed by conducting VES surveys adjacent to wells where
subsurface data are known. Researchers often correlate Dar Zarrouk parameters T and S
(transverse resistivity and longitudinal conductance) to aquifer characteristics, since they can be
determined more easily and uniquely than layer resistivity (p;) or layer thickness (h;). Several
studies have been conducted in the attempt to remove the effects of changing pore water
41.
-------
resistivity by normalizing the apparent transverse resistivity. They employ the use of a correction
factor (paJip,,) which is a subjective average water resistivity (p'^,) divided by the site specific pore
water resistivity (pw) (Ponzini and others, 1984; and Ahmed and others, 1988). Geostatistics have
also been used, to correlate the spatial variability of the data (Bardossy and others, 1986; and
Ahmed and others, 1988).
Niwas and Singhal (1981) proposed the combining of Darcy's and Ohm's laws, with Dar Zarrouk
parameters to form two new fundamental laws:
T = K • a • R and T = K / (a • C)
where: T = aquifer transmissivity
K = hydraulic conductivity
a = aquifer electrical conductivity = 1 / p
p = aquifer resistivity
R = transverse resistivity = h • p
C = longitudinal conductance = h / p
Niwas and Singhal propose that if K • p is constant for a given area, the hydraulic conductivity
can be correlated to aquifer resistivity as measured by surface D.C. resistivity surveys.
In general, these researchers found that for development of empirical correlations a large number
of field sites are needed within the area of interest. The data should span the entire range of
interest, since extrapolation beyond known data is questionable.
Fracture Systems
Migration of fluids in bedrock fractures and joints is primarily controlled by the orientation,
aperture, density and type of in-fill material. Surface D.C. resistivity studies of fracture systems
can be used to determine the location, orientation, degree of anisotropy, direction of greatest
interconnection, fracture porosity, and transmissivity anisotropy (Merkel and Kaminski, 1972;
Habberiam, 1975; Mallik and others, 1983; Smith and Randazzo, 1989; Stewart and Wood, 1990;
Ritzi and Andolsek, 1992; Haeni and others, 1993; al Hagrey, 1994; and Lane and other, in
press).
42.
-------
Merkel and Kaminski (1972) conducted radial profiles centered on production wells using a
modified djpole-dipole array where one of the current electrodes was placed in the well. They
found better delineation of the fracture systems when the well electrode was within a fracture
system.
Mallik and others (1983) found the axis of the apparent resistivity ellipse developed from radial
VES surveys compared favorably with surface-mapped fracture systems. Also, plots of the VES
anisotropy (X) versus electrode spacing indicated variations of fracture density with depth.
Taylor and Fleming (1988) proposed a method for azimuthal resistivity surveying in jointed rock.
They used the Wenner array in radial or azimuthal resistivity surveys to determine fracture
anisotropy, direction of greatest connectivity, and fracture porosity. They found the major axis of
the resistivity ellipse was parallel to the direction of greatest joint interconnection. When the
length of the fractures exceeds the array spacing, the major axis resistivity closely parallels the
strike of the most prominent set of fractures. When the length of the fractures is less than the
array spacing, the major axis of resistivity is oriented in the direction of greatest connectivity for
the combined set of fractures.
Ritzi and Andolsek (1992) used the method of Taylor and Fleming to determine the orientation
of the anisotropic transmissivity ellipse around a pumping well. The results of the azimuthal
resistivity survey compared well with the drawdown ellipse observed during a pumping well test.
They concluded that D.C. resistivity can be used to predict hydraulic characteristics of an aquifer
and can be used to locate wells.
The basic premise of radial or azimuthal resistivity surveys is that the resistivity ellipse, a polar
plot of apparent resistivity by azimuth, should indicate the direction through the fracture system
having the least hydraulic resistance. The authors all noted the paradox of resistivity anisotropy
described by Keller and Frischknecht (1966): for steeply dipping fractured or layered rock the
maximum apparent resistivity is measured along the strike of the fracture and the minimum is
measured on the perpendicular.
Lane and others (in press), and Haeni and others (1993) used an azimuthal square-array D.C.
resistivity method to map fractures in bedrock. They found that the square-array D.C. resistivity
sounding method is more sensitive to rock anisotropy than the Schlumberger or Wenner arrays.
43.
-------
The square-array D.C. resistivity method also requires 65 percent less surface area than the
Schlumberger or Wenner arrays (Habberjam and Watkins, 1967; and Habberjam, 1972).
Landfills and Waste Impoundments
Numerous investigation of landfills and waste impoundments using D.C. resistivity methods have
been reported in the literature (Cartwright and McComas, 1968; Warner, 1969; Klefstad and
others, 1975; Stollar and Roux, 1975; USEPA, 1978; Greenhouse and Harris, 1983; Grady and
Haeni, 1984; Ruby, 1984; Stierman, 1984; Rumbaugh and others, 1987; Stierman and Ruedisili,
1988; Robert, 1989; Barker, 1990a; Buselli and others, 1990; Butler and Llopis, 1990; Carpenter
and others, 1990 and 1991; Ross and others, 1990; and al Hagrey, 1992).
The general conclusions from these waste impoundment and landfill studies regarding the
applicability of D.C. resistivity survey to AMD investigations are: 1) the lateral and vertical
extent of landfills can be defined; 2) conductive leachate plumes from landfills and waste
impoundments can be mapped provided the geoelectric contrast caused by the pollution is
sufficient to overcome natural noise and scatter in formation resistivity; 3) the integrity of landfill
cap can sometimes be assessed and fractures identified; 4) the best results are obtained when the
ground water is shallow and the geology is relatively homogeneous.
Open and Filled Voids
Direct current resistivity has been used in combination with other geophysical methods such as
seismic refraction, microgravity, and ground penetrating radar, to locate subsurface voids that are
either filled with air, water or clay (Cook and Nostrand, 1954; Cook and Gray, 1961; Dutta and
others, 1970; Bates, 1973; Speigel and others, 1980; Denaham and Smith, 1984; Filler and Kuo,
1989; Smith and Randazzo, 1989; and Nelson and Haigh, 1990). These investigators generally
found that relative to surrounding rock, air-filled cavities exhibit very high to infinite resistance
and water- or clay-filled , low resistance. Filler and Kuo (1989) found that D.C. resistivity
delineated shallow limestone cavities where seismic and ground penetrating radar did not.
Nelson and Haigh (1990) found that resistivity surveys over air-filled sinkholes were effective in
finding caverns but not useful in locating the associated fracture systems.
44.
-------
Long-Term Monitoring
>.
The use of D.C. resistivity in conjunction with other geophysical methods for long term
monitoring of ground-water quality has been discussed by Wilt and Tsang (1985), Benson and
others (1988); Barber and others (1991); and Hanson and others, (1993). Long-term monitoring
using resistivity requires a reasonable understanding of the subsurface geology and hydrology,
knowledge of potential sources and geochemical nature of pollution, and development of
background or a baseline resistivity signature. Detection of change is complicated by seasonal
variations in soil moisture, ground-water levels, and changes in the direction of ground-water
flow. Monitoring highly conductive fluids such as AMD can be successful when the contrast with
background or baseline data can be distinguished from random noise and seasonal variations.
D.C. RESISTIVITY FIELD PROCEDURES
Direct current resistivity surveys can be conducted either as vertical soundings (VES) or
horizontal profiles. Soundings are conducted by expanding the electrode spacing over a fixed
point. Thus VES data are collected at discrete points and provide information on the vertical
change in layer resistivity and thickness. Horizontal profiles occur along linear or near-linear
trends, or when evaluating anisotropy along radial profiles. The intent of a profile survey is to
observe lateral changes or to define the extent of an anomalous buried target. Profile surveys
should be oriented to maximize the reading over the anomaly, generally perpendicular to the
strike of the target. However, special cases exist, such as azimuthal or radial surveys, where use
of various orientations can reveal important information.
Details of field procedures for D.C. resistivity are discussed by Soil Test (1968), Zohdy (1968b),
Mooney (1980), Milsom (1989), Telford and others (1990), and Ward (1990). The following is a
summary of recommendations for field work::
o For VES surveys, several sites should be selected to develop an understanding of the
range of resistivity and thickness. Site selection should be based on prior knowledge of
targets, actual subsurface data, estimates of subsurface geology, estimates of geophysical
response based on forward modeling, and locations where information would be of
maximum benefit. Accuracy of VES interpretations is maximized when some actual
subsurface data are available.
45.
-------
o Plot and evaluate VES survey data in the field to make adjustments in survey direction
and spacing, or method, and to detect errors in equipment and survey procedures.
i
o Several VES surveys should be run perpendicular to each other to develop an
understanding of the magnitude and impact of anisotropy.
o VES surveys should be conducted initially in areas where horizontal profiling is planned
in order to determine the appropriate electrode spacing(s). Mooney (1980) recommends
that the profiling array spacing be at least 11A to 2 times the target depth. Thus for the
Wenner array, the overall spread would be 4 to 5 times the target depth.
o To develop correlation between VES data and aquifer properties or ground-water quality,
surveys should be run adjacent to the production or monitoring wells. If the well casing is
conductive, the survey should be sufficiently distant enough that the well casing does not
interfere. Trial surveys may be needed to establish the proper distance.
o Because horizontal profiles are conducted to find lateral changes in the subsurface,
surveys should be run over targets. The lateral extent of the survey should be of
sufficient distance that the entire array is outside the target's influence. Lateral line
spacing and the associated probabilities of finding an target have been discussed above.
o If profiles are repeated to obtain information at various depths, then a reduction in
electrode spacing of between 1 to %, or an expansion in electrode spacing of 1 to 2 is
suggested.
o Data for VES surveys should be collected so that there are at least six data points per
decade. One decade is equal to a factor of 10 on the logarithmic scale. To obtain this
spacing, each new spacing is found by multiplying the previous value by 101* = 1.47.
Increment round-off is done in practice.
o For VES surveys the span of the data should be at least 2 decades with 2V2 to 3 decades
preferred.
o The small electrode spacings should be at least one-half the minimum depth at which a
change in material is expected.
o Resistance at the electrode should be minimized. This can be accomplished by: 1) using
non-polarizing electrodes, such as ceramic copper-sulfate pots; 2) placing metal electrodes
into moist earth; 3) using two or more electrodes connected in parallel and spaced a
meter or two apart perpendicular to the survey line; 4) pouring water or salt water around
the electrode.
o Surveys should be 1 to 2 electrode spacings away from sharp changes in topography, such
as cliffs or road cuts. Position the survey parallel to the contour of hill or breaks in slope
to minimize the impact of topography.
o As the spacing of the survey is widened, there is a tendency for the value of resistance to
decrease. However, increases or "backups" can occur when one current electrode is
placed in or above material of much higher resistivity, or the dip of the underlying layer is
46.
-------
changing rapidly. A new survey should be run at right angles to evaluate the cause of
the backup.
>>
o Electrodes should be seated in soils and not driven into gravels or rock. If penetration is
not sufficient where originally planned, offset the electrode at a right angle to the survey
• line.
MISE-A-LA-MASSE GEOPHYSICAL METHODS8
The mise-a-la-masse method or charged-body potential method is a three point resistivity method.
One of the current electrodes (positive pole) is placed into the conductive mass, usually an ore
body, and the other electrode is placed sufficiently distant so that its impact is negligible. Two
options exist for the configuration of the potential electrodes. One method measures the
potential gradient by moving two electrodes placed relatively close together over the area
surrounding the buried current electrode. The other method places one potential electrode at a
reference point at a distance sufficient to be considered infinite, several hundred meters from the
study area. The other potential electrode is then moved about to read the total potential
(Telford and others, 1990).
The application of the mise-a-la-masse method to subsurface investigations is similar to the self-
potential method, discussed below, and is used to obtain a general understanding of the lateral
extent of a conductive body. The method is most often used in mineral exploration to determine
the extent and interconnection between pyritic ore bodies (Parasnis, 1973). The method works
best when the conductivity of the target is 10 to 100 times that of the surrounding country rock
(Eloranta, 1984; and Beasley and Ward, 1986). Mise-a-la-masse surveys are often done in
conjunction with self-potential surveys because they can indicate the dip of the conductive body
better than the self-potential method (Bhattacharya and others, 1984).
Papers that document the use of mise-a-la-masse in environmental and hydrogeologic studies
include: delineation of fracture systems (Jamtlid and others, 1984; and al Hagrey, 1994);
estimation of ground-water flow direction and velocity; estimation of dispersion velocity from
tracer injection tests and infiltration tests (Mazac and others, 1980,1987 and 1992; Clasen, 1988;
Cahyna, 1990; and Kelly and Mares, 1993).
Reference begin on page 118..
47.
-------
Implementation of the mise-a-la-masse method requires that a'borehole or well be drilled into the
conductive mass or fracture system of interest. Measurements are made radially from the buried
electrode. At least two measurement points are needed on each selected azimuth in order to
determine the velocity of ground-water or plume. These measurements should be made away
from the buried electrode at a distance of at least IVz times the depth to the aquifer if the well is
non-conductive and three times the depth if the well is conductive (Mazac and others, 1992);
Maximum depth of exploration for ground water is approximately 10 meters with a radial
distance of approximately 150 meters (Jamtlid, 1984; Mazac and others, 1992).
INDUCED POLARIZATION GEOPHYSICAL METHODS9
GENERAL DISCUSSION
When direct current induced in the ground through electrodes is turned off, the drop in voltage,
as measured at two potential electrodes, is not instantaneous but decays exponentially over
several seconds to minutes of relaxation time. This delayed voltage response is due to an
induced polarization (IP) of the earth material. The cause of the polarization is not fully
understood but is thought to be a combination of electrode polarization and membrane
polarization (Sumner, 1976; Ward, 1990).
Electrode polarization is due in part to the presence of a diffuse double layer (DDL) of ions on
the surface of clay particles. This DDL is caused by a layer of exchangeable cations on the
surface of the negatively charged clay particles, making a double layer known as the Helmholtz
double layer (Bohn and others, 1985). In the presence of pore water, the cations are not as
tightly held to the surface and diffuse into the aqueous phase. The concentration of the cations
decreases exponentially away from the clay surface. The thickness of the DDL is defined as the
distance over which the solution concentration is affected by the charge of the clay particles. The
thickness (d) of the DDL can be described by the formula (Ward, 1990):
9Refermces begin on page 119.
48.
-------
d = K, • K • T / (2 • n • e2 • \)2)1/2
t
where: n = ion concentration of bulk solution
V = valence of ions
e = unit of electronic charge
K,. = dielectric permittivity of the fluid
K Boltzmann's constant, 1.38054 x 10"16 erg/°K
T = Temperature, °K
The thickness of the DDL layer increases with an increase in Ke and T, and decreases with an
increase in n and t>.
The movement of electrical current across the DDL can be done in two ways, faradaic and non-
faradaic. Faradaic transfer is caused by electrochemical reactions where charge is physically
carried across the interface by electron transfer. With non-faradaic transfer, no electrons are
transferred but charge is built up across the DDL. Non-faradaic transfer can be described as a
simple capacitor whose impedance varies with frequency. Electrode polarization can be
represented and predicted by a simple electrical circuit known as the Cole-Cole model of
relaxation (Ward, 1990).
A second mechanism for polarizability is termed membrane polarization and is important in rocks
and soils with a few percent clay. When an electric current is induced in the earth, membrane
polarization occurs within small diameter pores because the cations in the DDL block movement
of anions, but allow cations to move easily. This creates an ion-selective membrane (Ward,
1990). The ion concentration gradient that develops opposes the flow of current, reducing ion
mobility. This reduction in ion mobility is frequency dependant, the greatest occurring at low
frequencies (0.01 Hz). As the frequency increases, the ion-selective membrane effect becomes
less important and at approximately 1000 Hz no longer has an affect on the mobility of ions.
Variations in the polarizability of soil and rock can be an important phenomena in environmental
and hydrogeologic investigations. Polarizability can be defined as the ratio of the voltage
potential at a given time after the current is turned off, to the potential before the current is
turned off (Ward, 1990). The value is expressed as a percentage, given the term chargeability,
and derived by the formula (Ward, 1990; Kelly and Mares, 1993):
49.
-------
= [AV1P(ti) / AV^] • 100%
where: TI .,(!;) = apparent polarizability at time t;
AV,P(tj) = induced potential at time ti, mV
= primary potential, mV
The rate of discharge of voltage is given by:
«,P = VrftO / VIP(t2)
where: tx and t2 are two different times after the current is turned off
IP is similar to D.C. resistivity in that the ratio of the voltage output to the current input is a
measure of the impedance of the earth. IP surveys are conducted with electrode arrays similar to
D.C. resistivity surveys and are often done concurrently by using the value of voltage difference
at the peak of the current cycle.
IP surveys can be conducted as either vertical soundings (VES-IP), profiling or a combination of
the two. Analysis of data is similar to D.C resistivity. Computer modeling or master curves can
be used to determine vertical layering (Seigel, 1959; Dieter and others, 1969; Sadek, 1983;
Anderson and Smith, 1986; and Interpex, 1988), pseudo cross-sections can be constructed, and
contour maps of polarizability (chargeability) at equal electrode spacing can be used to interpret
subsurface features (Ward, 1990).
IP theory and array configurations, mathematical models for buried targets, are discussed by
Marshall and Madden (1959), Coggon (1973), Frische and Von Buttler (1957), Hohmann (1975
and 1988), and Fox and others (1980).
IP contrasts with D.C. resistivity in that there are two modes of data collection and
interpretation: time domain and frequency domain. In time-domain IP, a square waveform
primary current input is turned on and off periodically. Output voltage is measured at various
times after the current is turned off, typically between 0.5 seconds and 2 seconds. The decay
voltage at a time tt can be normalized by the primary voltage using the formula given above for
chargeability. The resulting units are millivolts/volt. This normalized voltage or chargeability is a
50.
-------
fundamental expression of IP polarizability. The decay curve can also be integrated over a time
period (VAt) and normalized by both VRA and At to yield a unit of millivolts-millisecond/volt or
milliseconds. A third method of analyzing time domain data is the Newmont method which is a
modification of the integration method. The standard Newmont IP cycle is 3 seconds on, 3
seconds off, and 1 second of integration time, and is typically written M331 (Ward, 1990).
The frequency-domain IP method, sometimes called complex resistivity, uses a continuous sine
wave of current as input. Output is measured in both real (Re) and imaginary (Im) (quadrature)
components. Amplitude (pa) of the apparent resistivity and phase shift (O) of the output voltage
waveform are given by (Ward, 1990):
Pa = (Re2 + Im2)172
4> = arctan(Im / Re)
In frequency-domain IP, the amplitude of the apparent resistivity and the phase shift can be
measured over several decades range in frequency (0.03 Hz to 300 Hz). In field applications this
frequency dependence of IP polarizability becomes important because it restricts the range of
frequencies used to between 0.03 Hz and 3 Hz. The low frequency is restricted by noise caused
by interaction of the earth's magnetic field with solar activity, while the high frequency is
restricted by electromagnetic coupling of the transmitter and receiver (Sumner, 1976; and Ward,
1990).
Results of frequency-domain IP are apparent resistivity measured at different frequencies. The
impact of frequency and polarizability can be quantified by comparing the apparent resistivity at
two frequencies. This is known as the percent frequency effect (PFE) and is given by (Ward,
1990):
PFE =
where: PI = apparent resistivity at frequency 1
p2 = apparent resistivity at frequency 2
For normal frequency-domain IP surveys, the PFE is positive, the phase shift lags (negative phase
angle), and the secondary decay voltage (output) has the same sign as the primary voltage
51.
-------
(input). Negative IP effects are possible and commonly cause a positive phase angle. Negative
IP effects can be caused by heterogeneities in the soil, inductive coupling, polarizability of type-K
and type-Q layer sequences, and some 2-D and 3-D bodies (Ward, 1990).
Inductive coupling has several causes including capacitive, cultural and electromagnetic (Sumner,
1976). Capacitive coupling is caused by electrical leakage from wire-to-wire, wire-to-ground, or
electrode-to-wire. Cultural coupling is caused by artificial, grounded conductors such as pipes,
fences, or power lines. Electromagnetic coupling is caused when the IP transmitter and receiver
circuits behave like primary and secondary windings of an electrical transformer. That is, the
primary circuit induces current into the secondary circuit. Electromagnetic coupling increases
with frequency.
USE OF IP IN AMD INVESTIGATIONS
Induced polarization has been used in conjunction with conventional D.C. resistivity studies to
explore for ore bodies, evaluate ground-water resources, investigate landfills, define limits of clay
layers, identify the fresh-water salt-water interface, and find source areas for saline ground-water
contamination (Vacquier and others, 1957; Breusse, 1963; Ogilvi, 1967; Ogilvi and Kuzmina,
1972; Bodmer and others, 1968; Cahyna, 1990, Cahyna and others, 1990; Draskovits and others,
1990; Ward, 1990; Sandberg, 1993; and Kelly and Mares, 1993).
Investigation of AMD using IP methods has not been reported in the literature, but the
environmental and hydrogeologic applications reported above suggest that IP methods can be
utilized. The following characteristics of IP methods apply to environmental and hydrogeologic
investigations:
o Polarizability is related to the particle size distribution. IP decay rate decreases with an
increase in the diameter of sand particles. That is, the larger the sand, the shorter the
relaxation time.
o Maximum IP effects occur when the clay content ranges from 3 to 10 percent. The lowest
polarizability is found in clean quartz sand, and pure clay. In water saturated sandstone
and alluvium, IP appears to be caused by clay coatings on the surface of sands and
gravels. .
52.
-------
o Flocculation and dispersion of clays can effect polarizability. Sodium and potassium
causes clays to disperse and swell, closing pores and reducing IP membrane effects.
Saturation with calcium causes clays to flocculate, increasing pore interconnection and
thereby the polarizability. For flocculated clays, polarizability is at a maximum at a clay
content of 5 to 9 percent.
o Polarizability of clay appears to be directly related to the cation exchange capacity.
Montmorillonite has a higher polarizability than kaolinite.
o Polarizability of water saturated soils is generally higher than that of for partially
saturated soils.
o Specific conductance of pore water can effect the polarizability. The IP decreases with an
increase in salt concentration. IP decays more rapidly with an increase in pore water
salinity. At a salinity greater than 10 grams per liter, IP is negligible. IP is most strongly
affected by cations whereas anions such as Cr, SO42', and fOf, cause almost no change.
IP decreases with an increase in cation valence. For alkaline soils, the polarizability is
greater than neutral soils.
o Generally, polarizability decreases with decrease in resistivity. Thus clay horizons and
saline water give smaller anomalies.
o Polarizability is nearly constant at temperatures as high as 40°C. At greater temperatures,
IP declines. At temperatures below 0°C polarizability increases in coarse materials, but
remains almost constant in clays.
o The signal-to-noise ratio for IP is often better than for D.C. resistivity in shaley
sandstone.
Barker (1990) used IP to investigate saline polluted ground water and found it performed better
than D.C. resistivity for low levels of pollution in shaley sandstone. Griffiths and others (1981)
traced the flow of NaCl pollution from an old foundry spoil pile along fissures caused by collapse
of underground mine workings. The low resistivity and high chargeability aligned with the
suspected fissures. Chargeability increased when Cl' concentrations rose from 5 to 500 mg/1, but
decreased above 500 mg/I.
Mazac and others (1990) found that there is no relationship between IP and aquifer hydraulic
conductivity. Cahyna and others (1990) investigated ground-water contamination associated with
a foundry slag pile that contained heavy metals. Their laboratory studies showed the
polarizability and resistivity of the slag to be higher than that of the surrounding country rock.
However, field studies found that only IP could delineate the slag, and that high IP chargeability
was associated with concentrated sources of ground-water pollution.
53.
-------
Although IP methods are most commonly used for mineral exploration, they can be applied to
environmental investigations including AMD. Problems with implementation of IP surveys in
AMD studies would include: noise caused by heterogeneities'of the waste piles, reduction in
polarizability due to increase in solution concentration, and the unknown effects of metal
hydroxide precipitates on interconnection of pores and polarizability.
ELECTROMAGNETIC METHODS10
GENERAL DISCUSSION
Electromagnetic (EM) geophysical surveys involve the use of frequency-domain or time-domain
electromagnetic fields to map near-surface geologic features by identifying variations in the
conductivity or resistivity of soil and rock. Frequency-domain and time-domain EM surveys can
be done on the ground, in fixed-wing aircraft or helicopters (Telford and others, 1990).
Frequency-domain EM methods include conventional very low frequency (VLF), VLF resistivity,
audio-magnetotelluric, controlled source audio-magnetotelluric, slingram, ground conductivity
meters and bore-hole methods. Time-domain EM methods include fixed-loop slingram and
central-loop configurations (McNeill, 1990). As with conventional resistivity methods, EM
methods can be used to identify and map subsurface geologic features using variable spacing for
vertical soundings or fixed spacing for cross-sectional profiles. EM methods can also be divided
into two categories based on the nature of the source wave, either planar or loop. The planar
wave is considered to propagate across the earth's surface as a uniform, horizontal wave form.
The loop wave is generated by a local magnetic dipole. Details on the physics of EM methods
are discussed by Telford and others (1976,1990), Parasnis (1973,1986), Sharma (1986), Dobrin
(1976), and Keller and Frischknecht (1979).
EM methods commonly used in ground water and environmental investigations include VLF,
fixed-spacing frequency-domain, ground-conductivity meters, and center-loop time domain.
These methods are most often used because of the commercial availability of EM systems,
portability, relatively rapid data acquisition, and ability to give relatively good
resolution of the subsurface. Table 6 is a summary of EM geophysical survey methods (McNeill,
1990).
References begin on page 122.
54.
-------
Table 6
Summary of Electromagnetic Survey Methods11
EM Method
Conventional
VLF
VLF
Resistivity
Audto-
Magnetotelluric
(AMT)
Controlled Source
Audio-
Magnetotelluric
(CSAMT)
Frequency Domain
Slingram
Frequency
Single
Single
Broadband
Broadband
Multiple fixed
frequency
Parameter
H
E, H,<|>
E,H
E.H.<>
B
Principal
Application
Mapping
Structures
Soundings
Soundings
Soundings
Mapping structure;
Soundings
Advantages
Very fast, One
person operation;
Inexpensive;
Works well at high
resistivity levels
Very fast, One
person operation;
Inexpensive;
Works well at high
resistivity levels
Relatively fast;
Inexpensive;
Under optimum
conditions gives
good sounding data;
Works well at high
resistivity levels
Fast;
Under optimum
conditions gives
good sounding data;
Works well at high
resistivity levels
Relatively fast for
structural mapping
and soundings;
Relatively
inexpensive;
Good measure of
bulk conductivity in
conductive ground
Disadvantages
Shallow depth;
Depth limited by
conductive surface;
Provides limited
subsurface
information;
Sensitive to
transmitter direction;
Areas of little to no
signal strength
Shallow depth;
Depth limited by
conductive surface;
Resolves at most
two layer;
Areas of little to no
signal strength;
Static shin
Signal strength
varies;
Sensitive to source
orientation;
Static shift
Expensive;
Static shirt;
Transmitter overprint
Limited ability to
sound;
Zero error;
Coil alignment and
spacing critical;
Surveys difficult in
uneven terrain;
Poor results in
resistive terrain
"Table modified after McNeill, 1990
55.
-------
Table 6(continued)
Summary of Electromagnetic Survey Methods
EM Method
Ground
Conductivity Meter
Time-Domain EM
(TDEM)
Frequency
Multiple fixed
frequency
Varies current
with time
Parameter
B
dB/dt
f
Principal
Application
Mapping
conductivity and
structure;
Simple soundings
Mapping structure;
Soundings
Soundings
• Advantages
Fast for structural
and conductivity
mapping;
Relatively fast for
soundings;
Relatively
inexpensive;
Good measure of
bulk conductivity in
conductive ground
High degree of
survey flexibility;
Moderately fast;
Insensitive to
intercoil spacing and
alignment;
Zero level well
known;
Good measure of
bulk conductivity in
conductive ground;
Very fast;
Good lateral
resolution;
Good resolution of
equivalence;
Good measure of
bulk conductivity in
conductive ground
Disadvantages
Very limited
sounding data;
Shallow exploration
depth (<60m);
Non-linear response
at high conductivity;
Poor results in
resistive terrain
Relatively
expensive;
Poor results in
resistive terrain
Relatively
expensive;
Poor results in
resistive terrain
H = Magnetic field strength
E = Electrical field strength
d> = Phase difference between E and H
56.
-------
VLF METHODS
*
Conventional VLF
Two methods of VLF geophysical surveying are employed in environmental studies: conventional
VLF and VLF resistivity. Both methods rely on electromagnetic fields being transmitted by a
distant VLF transmitter. VLF transmitters are worldwide and transmit at frequencies in the band
of 15-25 kHz (kilohertz) for the purpose of military, air and marine communications (Parasnis,
1986; Telford and others, 1990). The VLF transmitter antenna is an oscillating electrical dipole
that is effectively a grounded vertical wire several hundred meters long. The electric and
magnetic fields radiate as ground, space and ionosphere waves. At distances much greater than
the wave length, 20 kHz = 15 km, the field of the VLF dipole can be considered a uniform field
within a small area of several kilometers (km) (Telford and others, 1990). These uniform VLF
waves consist of three fields, a vertical electrical field, a horizontal magnetic field perpendicular
to the direction of the wave propagation, and a small horizontal electrical field oriented with the
direction of wave propagation. There is no vertical magnetic field (McNeill, 1990).
Conventional VLF geophysical surveys measure components of the magnetic field. Recent
studies by McNeill and Labson (1990) have shown that the VLF anomaly is caused by a
subsurface horizontal electrical field that induces electrical charges at the interface between two
materials of differing resistivity rather than from induced eddy currents as previously thought.
Conventional VLF response is greatest when the buried conductor strikes in the direction of the
wave propagation, and the response strength falls off with the cosine of the angle between the
conductor strike and the wave direction (McNeill, 1990).
Depth of exploration is limited to 60 to 70 percent of the skin depth, 8, as determined by the
following formula:
8(m) « 500 • (p / \>)w
where: p = earth's resistivity, Q-m
v = wave frequency, Hz
57.
-------
This depth of exploration can be shallow (McNeill, 1990). For example, for a 25 Q-m material
and a wave frequency of 15 to 25 kHz the skin depth is approximately 10 to 15 m.
Conventional VLF geophysical surveys are performed using the following steps (McNeill, 1990;
and Parasnis, 1986):
o The presence of a conductor causes a secondary magnetic field out-of-phase with the
primary horizontal magnetic field, creating an elliptically polarized magnetic field.
o The VLF instrument has two solenoids aligned in the same plane, one vertical and one
horizontal.
o The vertical solenoid is rotated until the minimum signal is obtained. In this orientation
the vertical solenoid is aligned with the minor axis of the secondary ellipse of polarization
and is perpendicular to the major axis. The tilt angle, 6, from the vertical is equal to the
angle between horizontal and the major axis of the ellipse of polarization.
o The second, horizontal solenoid measures the strength of the major axis field.
o The ratio between the signal strength of the vertical solenoid (minor axis, b) and the
horizontal solenoid (major axis, a) is termed the VLF eccentricity.
o The tilt angle measures the in-phase or real component of the secondary vertical magnetic
field. While the ratio of b/a is a measure of the quadrature or imaginary component.
Although the field strength is reduced if the conductor is not aligned with the VLF wave, the tilt
angle and the b/a ratio are not significantly changed. VLF surveys have several problems that
limit their application (McNeill, 1990; and Parasnis, 1986). Conductive overburden and variations
in the thickness of overburden can generate significant VLF anomalies. VLF is influenced by
topography and readings increase positively going uphill and negatively going downhill (Parasnis,
1986). Adjacent anomalies are superimposed and special filtering is necessary to resolve
individual responses. In some areas of the world, VLF signal strength is too weak and a portable
transmitter is necessary.
VLF Resistivity
Measurement of the ratio of the amplitudes of the horizontal electric and magnetic VLF fields at
the earth's surface can provide an apparent resistivity using the following formula (McNeill,
1990):
58.
-------
where: pa = apparent resistivity, fl-m
IEI = amplitude of horizontal electrical field,
volt/meters
| H | = amplitude of horizontal magnetic field,
ampere/meter
p,0 = 4 • n x 10"7 Q-sec-nr1 (magnetic permeability of free
space)
to = 2 • jt • v
\) = wave frequency, Hz
In practice, the phase angle by which the horizontal electrical field leads the horizontal magnetic
field indicates whether resistivity increases or decreases with depth. For a homogeneous half-
space, a phase angle of 45° would be read. A greater angle indicates resistivity decreases with
depth, and a lesser angle reflects an increase in resistivity (Brooks and others, 1991).
Unfortunately, assumptions need to be made about the upper layering in order to calculate the
true resistivity (McNeill, 1990). Thus the method has difficulty resolving more than two layers.
A forward modeling computer program is available for VLF interpretation (Grantham and
Haeni, 1986).
AUDIO-MAGNETOTELLURIC AND CONTROLLED SOURCE
AUDIO-MAGNETOTELLURIC METHODS
Two EM methods that are not usually used for environmental investigations are the audio-
magnetotelluric (AMT) and controlled source audio-magnetotelluric (CSAMT). The AMT
method relys on naturally occurring electomagnetic fields in a frequency band of 1 Hz to 20 kHz
(lightning strikes). The CSAMT method is similar to AMT but uses a transmitter for a source
(McNeill, 1990). Both methods measure the ratio between horizontal electrical and horizontal
magnetic fields as a function of frequency to estimate an apparent resistivity. The frequency
dependent apparent resistivity is modeled using a computer to estimate a simple geoelectric
section. Although the AMT method is easy to implement, errors caused by static shift can lead
to problems with interpretation. Static shift is caused by electrical charges that are induced at
59.
-------
the contact between layers of different resistivity which strongly amplify the local fields. Errors
of one order of magnitude in resistivity and thickness are possible. AMT also needs a strong
signal and minimal 50/60 Hz power line noise. The CSAMT method can be used to overcome a
weak source. A problem arises in the need to separate the transmitter from the site of
investigation by a distance of at least three skin depths. For a source operating at 10 Hz in a
1000 ii-m ground, a minimum separation distance of 15 km is needed. The local geoelectric
setting of the transmitter site can also overprint the investigation site readings and introduce
significant error.
Syed and others (1985) used CSAMT to locate improperly plugged oil wells that were leaking
saline brine into a shallow aquifer. To date, there is insufficient research in using CSAMT at a
geologically complex site (Bartel, 1990).
FREQUENCY-DOMAIN SLINGRAM
AND GROUND CONDUCTIVITY METER METHODS
The EM method most often used for environmental studies, which is a variation of the slingram
method, employs the ground conductivity meter (McNeill, 1990). The slingram method consists
of using two magnetic dipole loops connected by a fixed length cable. Loops can be in any
orientation but the most common methods require that both the transmitting and receiving loops
be aligned in either horizontal (vertical dipole) or vertical (horizontal dipole). The geophysical
survey is conducted by moving the loops across the earth at a fixed interval. The coils can be
operated at multiple frequencies and separation distances to obtain either vertical soundings or
cross-sectional profiles of the conductivity of the earth's layers.
•
The receiving loop measures the strength and phase shift of the secondary field generated by
subsurface conductors. The secondary field induced into a subsurface conductor will generally
differ in phase with the transmitted, primary field by a phase difference angle, 6. The vector of
the secondary field strength, Hs can be broken into two components: a component parallel to
the primary field, the in-phase or real component (H$ • cos6), and a component 90° out-of-phase,
the quadrature or imaginary component (Hs • sin6) (Parasnis, 1986). To measure the in-phase
component, the coil alignment and the intercoil spacing must be carefully maintained. This is
often difficult in uneven terrain. The vertical dipole method (horizontal loop) is sensitive to
60.
-------
narrow conductive zones or keels, and to conductive overburden whose extent is equal to or
greater than the intercoil spacing. The vertical dipole method:is also sensitive to steeply dipping,
poor conductors such as water filled fractures. The horizontal dipole method (vertical loop) is
less sensitive and is often the preferred coil orientation for geologic studies (McNeill, 1990).
Slingram systems are influenced by conductive overburden. The primary EM field decreases by
1/e at the skin depth with a phase change of 1 radian (57.3 degrees) (Parasnis, 1986). For
overburden thickness of less than the skin depth, the attenuation and phase change is
proportionally smaller. Thus the phase of the field exciting the subsurface conductor is not the
same as that of the transmitter. The secondary field from the conductor as measured by the
receiving coil is likewise influenced by the overburden. The effect of conductive overburden is to
channel the primary field currents into the subsurface conductor where the current density is
higher than would be expected. The channeling effect increases with increased frequency as long
as the depth of the overburden is much less then the skin depth. At high frequencies, the
primary currents in the overburden are at the surface and screen the subsurface, eventually
causing the anomaly to disappear.
Ground conductivity meters differ from the conventional slingram system because (McNeill,
1990):
o The low operating frequency, or low induction numbers as defined below, means that the
receiver responses are mostly in the quadrature phase which is linearly proportional for
low to moderate ground conductivity.
o Ground conductivity meters are one order of magnitude more sensitive than the slingram
systems due to operation at low induction numbers, operating frequencies low enough so
that the skin depth is always significantly greater than the intercoil spacing.
o The quadrature zero level is set at the factory and remains nearly constant. This results
in an accurate and constant measure of the bulk ground conductivity.
o The horizontal and vertical dipole methods give differing depth responses. The horizontal
dipole responds to the subsurface within approximately 75 percent of the intercoil spacing,
while the vertical dipole responds to the subsurface within 150 percent of the intercoil
spacing (McNeill, 1983 and 1990).
o The maximum intercoil spacing is 40 meters, which is less than conventional slingram
systems.
61.
-------
Two commonly used EM ground conductivity systems, EM31 and EM34-3, are produced by
Geonics Limited. These instruments are operated at fixed intercoil spacings and frequencies and
give direct readings of apparent ground conductivity. As with the slingram systems, the receiving
coils of these instruments sense the secondary magnetic currents, H,, and compare them to the
primary field, Hp, for specific frequencies so that they operate at low-value induction numbers.
The induction number is defined as the ratio of the intercoil spacing to the skin depth (s/8).
When the induction number is much less than unity (McNeill, 1980):
H,/HP
where: H, = secondary magnetic field at the receiver coil
Hp - primary magnetic field at the receiver coil
co = 2 • TI • i)
v = frequency, Hz
fi0 = permeability of free space, Si-sec-nr1
c - ground conductivity, mho/m
s = intercoil spacing, m
i = (-!)»
Thus the apparent ground conductivity value, in mho-nr1, given by the instruments is equal to:
ca = 4/(co./t0-s2-[H,/Hp]
Figures 5a and 5b show the normalized response curves, <|>v(z) and 4>h(z) and cumulative response
curves, Rv(z)and Rh(z), normalized to a "z" value that is found by dividing the depth to a layer by
the intercoil spacing. The <(>(z) function is the relative contribution to the secondary magnetic
field from a thin layer at a depth of z. The R(z) function is the relative contribution to the
secondary magnetic field from all material below a depth z, or cumulative response curve
(McNeill, 1980).
62.
-------
15
20 Z
Figure 5a: Normalized depth (z) versus relative instrument response <(>(z) curves for
vertical and horizontal dipoles for frequency domain EM (from McNeill,
1980).
l-Op
05-
Figure 5b. Normalized depth (z) versus cumulative instrument response R(z) curves
for vertical and horizontal dipoles for frequency domain EM (from
McNeill, 1980).
63.
-------
TIME-DOMAIN EM METHODS (TDEM)
^
Another EM method TDEM varies the current in the primary field with time rather than
providing a continuous alternating wave (frequency-domain). The transmitting coil is energized
with a steady electrical current. A constant magnetic flux is inducted into the subsurface but no
secondary currents are created because the flux does not vary with time. When the primary
current is abruptly turned-off, the primary flux falls to zero and creates transient secondary
currents within subsurface conductors because the flux is varying with time. The time dependent
decay of the magnetic field induces transient electromotive forces into the receiving coil
(McNeill, 1990; Parasnis, 1986). Environmental studies employ two methods of TDEM: the
slingram and the central loop.
The slingram method is similar to the frequency-domain methods. That is, small transmitter and
receiver loops are moved along at a fixed separation and a cross-sectional profile of the earth is
obtained. Vertical sounding can be made by varying the intercoil separation. The TDEM
slingram method has three important differences from the frequency-domain slingram method
(McNeill, 1990):
o TDEM is less efficient, therefore the transmitting loop must be large or multi-turn in
order to create a large dipole moment. Common dimensions are 5 m square.
o Constraints of the precision of intercoil spacing and alignment are less for TDEM
because measurements are made while the transmitter is off.
o Zero level of the receiver is more accurate with TDEM because measurements are made
while the transmitter is off.
The second TDEM method uses a large transmitting loop, typically 20 to 150 meters square, with
a small receiving loop in the center of the transmitting loop or at the outer edge. Placement of
the receiving coil at a distance equal to the side length of the transmitter loop can reduce the
magnitude of the inaccuracies caused by induced polarization (IP) effects. When the primary
field is turned off, horizontal eddy currents are instantly generated near the transmitting loop that
try to maintain the magnetic field at the same strength as before the current was turned off.
These eddy currents increase in depth and expand radially with time. The decay of the magnetic
field is a measure of the resistivity of the subsurface as a function of depth. TDEM has the
. following advantages over conventional D.C. resistivity for deep sounding (McNeill,1990):
64.
-------
o TDEM is faster to cany out. The rate of surveys can be increased by laying out several
transmitting loops with the transmitter, receiver and receiver loop moved along to collect
data.
o Depth of exploration of TDEM sounding is larger than the array dimension unlike D.C.
• resistivity which must have an array length several times the depth of interest.
o The central loop method is insensitive to overburden conductivity variations and local
inhomogeneities.
o The problem of equivalence is less for TDEM than for D.C. resistivity. However, D.C.
resistivity is superior to TDEM at resolving the resistivity and thickness of intermediate
resistive layers.
o Depth of exploration of the TDEM method is greater than that of the slingram method
and can be up to several kilometers.
USE OF EM METHODS IN AMD INVESTIGATIONS
EM methods have been used for the past 20 years for evaluating subsurface geology, subsurface
hydrology and water quality. Although EM methods provide information on the subsurface
geoelectric layering that is often less precise than D.C. resistivity data, the ease of use and the
rapidity of obtaining data make it a preferred method for shallow environmental studies,
especially for reconnaissance investigations. In recent years numerous environmental studies
have used EM methods. Geonics Ltd. (1992a, 1992b) has published two extensive bibliographies
of studies and reports on EM geophysical methods used for:
o agriculture soils mapping;
o archaeology investigations;
o mapping underground voids in limestone;
o locating underground tanks;
o defining depth and extent of permafrost zones;
o predicting the need for cathodic protection;
o landfill siting and monitoring;
o mapping sites of disposal of manufacturing waste,
radioactive waste, mining waste, and petrochemical waste;
o mapping higher permeability aquifer channels;
o mapping the extent of contamination in aquifers;
65.
-------
o mapping anisotropy in the subsurface;
o ^ defining the extent of weathering, fracturing an'd faulting;
o identifying areas of higher ground-water yield;
o mapping the saltwater-fresh water interface;
o defining the extent of protective clay layers;
o exploration for mineral deposits; and
o exploration for petroleum reserves
While the studies listed by Geonics do not all specifically address AMD problems, many of them
evaluate geologic and ground-water settings that are similar to those found at mine sites. The
two Geonics bibliographies are a valuable resource and can be obtained from Geonics Ltd. in
Mississauga, Ontario, Canada, at telephone (905) 670-9580, fax (905) 670-9204.
Published reports of EM investigations of AMD problems are limited and most studies were
conducted in coal mine areas rather than the pyritic hard rock mines of the western United
States. Greenfield and Stoyer (1976) conducted one of the earliest studies. They ran four
profiles in a Pennsylvania strip mine across areas of potentially high AMD ground-water flow
using horizontal and vertical dipole EM at 40 and 60 meter spacings. They also ran D.C.
resistivity profiles for more detailed layering information. Their study identified a fracture zone
that produced a high EM anomaly due to increased saturation by high specific conductance AMD
(« 330 mmhos/m). They also noted that the same fracture system might produce a low EM
anomaly during a drought because of more rapid drainage.
Ladwig (1982) conducted EM studies at three reclaimed coal mines that ranged in surface area
from 15 to 37 acres (6 to 15 hectares). Chemical concentrations of the AMD at the three sites
ranged from 20 to 4000 mg/L acidity, 18 to 800 mg/L iron and 200 to 1800 mg/L sulfate. EM
profiles using 10- and 20-meter intercoil spacing were able to identify areas of buried refuse with
high pyrite content, areas of shallow AMD ground water, source areas for surface seeps, a
subsurface drain, and delineate the previously unknown extent of the surface mine excavation.
Brooks and others (1991) used a ground conductivity meter (EM34) at a 10-meter intercoil
spacing and VLF resistivity (EM16R) over an abandoned Indiana underground and surface coal
mine. Specific conductance of the acidic ground water ranged from 3,000 to 18,000 jimhos/cm.
Results of the EM surveys were combined with drill hole logs and monitoring well water quality
66.
-------
data to infer sources of ground-water contamination, and to delineate the hydrologic connection
between w^ste rock with a high percentage of pyrite (4 to 10 percent) and the surrounding
undisturbed materials. A high conductivity anomaly near an adjacent stream was inferred to
indicate a connection between the stream alluvium and the underground mine workings.
More recently, studies of geophysics application to AMD problems have been conducted by King
and Pesowski (1993,1991), and King and Sartorelli (1991). These studies found that VLF
resistivity and EM ground conductivity meter surveys could delineate conductive plumes leaking
from drilling fluid disposal pits, an abandoned uranium mine, and from brine and tailing storage
facilities. They also used EM methods to delineate buried channels beneath a proposed tailings
storage facility.
To further evaluate the potential application of EM investigations to solving AMD problems,
other studies of conductive ground water pollution with EM were reviewed. The studies of
interest to AMD investigations can be classified into three general categories: 1) subsurface
geologic interpretation; 2) mapping saline brine; and 3) monitoring and mapping leachate from
landfills.
The use of EM methods to interpret the subsurface geology relies on a correlation between
geologic layering and conductivity contrasts. In natural geologic materials, conductivity contrasts
occur due to variations in porosity, permeability, grain size and pore water quality (see discussion
of geochemical and geophysical relationships, page 6). At a mine site where AMD pollution is
present, the ability to use conductivity contrasts to delineate subsurface geology can be restricted
by the random noise caused by heterogeneities of the waste piles, migration of very high specific
conductance AMD fluids into different geologic units (which masks the natural differences), a
lack of knowledge about man-made subsurface conditions such as the depth to a mine excavation
or waste fill, and the lack of knowledge about the location of subsurface openings.
Nevertheless, EM geophysical methods have successfully delineated the general nature of
subsurface layering in several studies including: Morgenstern and Syverson (1988), Sanders and
Cox (1988), Monier-Williams and others (1990), Mazac and others (1990), Lawrence and
Boutwell (1990), and Wrightman and others (1992). The use of EM for investigating saline fluids
or fluids with high total dissolved solids is discussed by: Slaine and Greenhouse (1982), Barlow
and Ryan (1985), Stewart and Brentnall (1986), Lyverse (1989), Stewart (1990), Sartorelli and
67.
-------
others (1990), Goldstein and others (1990), Barker (1990), Street and Engel (1990), Lahti and
Hoekstra (1991), Hoekstra and others (1992), and King and Fesowski (1993). The use of EM for
v l
investigating and monitoring landfills is discussed by: Slaine and Greenhouse (1982), Greenhouse
and Harris (1983), Lasky (1985), Greenhouse and Slaine (1986), Jansen and others (1992), and al
Hagrey (1992).
Interpretation of EM data for environmental studies is often done by comparing line plots of EM
readings taken at different times or along a traverse, contouring a plan view of data from a
surveyed grid, or conducting forward and/or inverse 1-D or 2-D modeling to create geoelectric
cross sections. 'Greenhouse and Slaine (1982, 1986) recommended that EM data be normalized
to either an arbitrary constant background value or a value taken at the initial sampling (time =
0), and that the results be expressed in terms of decibels (dB) using the following formula:
^decibel = 20 • 10gu(0v
where: a^ = apparent ground conductivity at a point x,y
background apparent ground conductivity
Normalization of the conductivity has the following three advantages over the use of actual
values:
o Normalization to a zero background puts all instrument readings on a common format
and allows comparisons of data between instruments of differing sensitivity.
o Logarithmic contour lines do not cluster around contaminant sources to the degree that
linear data do.
o The procedure is objective except for the selection of the constant background value.
By expressing the apparent conductivity in decibels it is often easier to view contrasts and
changes over background or initial values. A conductivity value of zero dB indicates no change
over background, a value of +6 dB is equal to twice background, and a value of -6 dB is equal to
one-half background. Slaine and Greenhouse (1982) suggest that a noise level of approximately
4 dB (or 1.6 times background) should be anticipated. Greenhouse and Slaine (1986) propose
the development of a "standard section" on which a 1-D sensitivity model is run to evaluate the
impact of variations in layer thickness and layer conductivity. Based on the model results, a
68.
-------
normalized background, uncontaminated section can be selected. Greenhouse and Slaine (1986)
introduce die concept of a "formation ratio" and a "surface ratio" which are the ratios of the
conductivity of individual layers and of the whole section to the background section. They
suggest that a formation ratio of at least 2 times background is needed to create a surface ratio
of 1.5 times background. Also, a threshold value of as much as 6 times the background is needed
to provide reliable evidence of contamination at a single station. Greenhouse and Slaine (1986)
noted that contoured data can provide a more reliable indication of contamination over plots of
single station data.
Monier-Williams and others (1990) found that topography had a significant influence on EM
surveys of landfills due to a reduction in the depths to ground water and an underlying clay layer
as the surface elevation decreased. Adopting the decibel normalization method of Greenhouse
and Slaine, they suggested an empirical method for correcting the effects of topography. In
effect a function, a(h), relates the surface elevation to the apparent conductivity of
uncontaminated ground. The function a(h) is then substituted for abackgrouild in the Greenhouse
and Slaine formula.
An alternative method for removing the effects of topography is to calculate the apparent
conductivity at the water table. Using EM data and depth to the water table measured at two
wells, Emilsson and Wroblewski (1988) simultaneously solved McNeilTs 2-layer case equations to
find the conductivity at the water table. For more complex layering, forward computer modeling
can be used to predict the impacts of topography and overlying layer thickness. Contouring of
the depth, thickness, or the Dar Zarrouk parameters of a geoelecrric layer based on forward or
inverse computer modeling (Interpex, 1988; and Grantham and others, 1987) can provide a better
definition of anomalies because the noise from other layers is removed.
Lawrence and Boutwell (1990) have suggested that when detailed subsurface data are available
from drill holes and monitoring wells a multivariate regression analysis can develop a correlation
between EM signature and geologic layering. They recommend that a minimum of 5 data points
be used to develop such correlations.
Mazac and others (1990) suggest a method for site-specific correlation of hydraulic conductivity
and surface geoelectrical measurements for both the saturated and unsaturated zones for porous
and fractured rock. The relationship between hydraulic conductivity, K, and resistivity, p, is non-
69.
-------
linear, but can approach linear for some parameters within a limited range. They propose a
method by which observed or interpreted parameters are placed into subclasses, each with a
specific weighting factor. The sum of the weights pertinent to all parameters, expressed as a
percent, gives an integral indicator value, I. The integral indicator value can be contoured and a
linear relationship between saturated K and I can then be found. Once developed for a specific
site, the K-I relationship can be used to delineate areas of differing hydraulic conductivity.
EM FIELD PROCEDURES
EM surveys are conducted similarly to other surface geophysical surveys. That is, the assumed
target area(s) is (are) identified; the objectives of the survey are defined; based on sensitivity and
applicability the proper EM methods are selected; and the survey points and grid are laid out.
EM surveys at mines often focus on known or observed sources of AMD seepage rather than the
entire site. EM surveys for AMD at mine sites can be complicated by a lack of knowledge about
historic operations, by abandoned and buried metal objects, and by the roughness of the terrain.
The following are general procedures recommended for EM surveys (McNeill, 1980, 1985b, and
1990; Geonics, 1988). For specifics on instrument calibration and operation the operating
manual should be consulted (Geonics, 1985a and 1991).
o Select target area and determine orientation of feature of interest, if possible.
o Optimize sample point and line spacing, intercoil separation based on results of test lines,
knowledge of target dimensions and depth.
o Determine whether ground conductivity contrast is sufficient to identify the plume or
buried object of interest. Use knowledge of uncontaminated materials and estimates of
contaminant concentration and specific conductance for a preliminary model instrument
response.
o Target should have an apparent ground conductivity that is at least 150 percent above or
below background.
o Lay out grid and identify sample points with non-conductive stakes or markers.
o Calibrate instrument at site as required by manufacturer.
o Orient traverses perpendicular to strike of target, if possible.
70.
-------
o Extend traverse lines into areas of no contamination, if possible. For point monitoring,
select stations within and outside of the plume. Select; a background site to obtain a
normalization value.
o Avoid areas of irregular topography, if possible, because variations from the ideal half-
space model can introduce error. Run survey lines along contour of slopes, if necessary.
o To determine the degree of anisotropy, take readings at a station at differing azimuth
orientations to find anisotropic ellipse.
o Determine extent of interference from fences, powerlines, and pipes by making a traverse
perpendicular any such features until EM readings stabilize.
o EM horizontal dipole (vertical coils) is sensitive to:
o near surface variation in conductivity;
o overhead powerlines, keep receiver furthest from powerline;
o fences, buildings and tanks, experiment to find safe distance; and
o near surface metal debris.
o EM vertical dipole (horizontal coils) is sensitive to:
o subsurface variations in conductivity;
o lithologic changes from faults;
o pipe lines;
o vertical dikes; and
o shallow buried metal debris.
o Data collection using written notes and data loggers can significantly speed up field survey
time and data processing.
o Written notes are essential. Data loggers can introduce error when station location or
instrument settings are not set properly. Errors are recoverable provided written notes
document starting and ending locations and station numbers, line orientations, intercoil
spacings, station spacings, field personnel, dipole orientation, and other critical survey
information.
SELF POTENTIAL METHODS (SP)12
GENERAL DISCUSSION
Self potential (SP) voltages occur in the subsurface due to natural electrochemical, electrokinetic
or thermoelectric reactions. These potentials are associated with weathering of sulfide mineral
bodies, variations in mineral content along geologic contacts, bioelectric activity, corrosion, and
References begat on page 127.
71.
-------
thermal or pressure gradients in fluids. There are four principal mechanisms that produce self
potentials:^) electrokinetic or streaming; 2) diffusion or liquid" junction; 3) Nerst or shale; and 4)
mineralization (Telford and others, 1990).
Electrokinetic potential, also called electrofiltration, and streaming or zeta potential, is caused
when an electrolyte flows through a capillary or more accurately a porous media. The result is a
potential difference between the ends of the passageway that can be expressed by the formula
(Parasnis, 1986):
Ek = -{£-p-C-P}/{4-TT-/i}
where: £ = dielectric constant of electrolyte, Fnr1
p = resistivity of electrolyte, ii-m
£ = streaming potential, V
/x = dynamic viscosity, Pa-sec
P = pressure gradient, Pa-nr1
Dielectric constant is a measure of the electric polarization that occurs when an electric field is
applied and varies inversely with frequency (Telford and other, 1990). The dielectric constant is
the ratio of the specific capacity of the material to the specific capacity of a vacuum (8.85 x 1042
farads per meter, Keller, 1989). Dielectric constant of a rock or soil material changes with water
content because water has a high dielectric constant, approximately 80 F-nv1 (see Tables 6 and 7
in Keller, 1989; and Table 5.5 in Telford and others, 1990).
Streaming potential can be found associated with flow of water through porous media. The
streaming potential is a double layer potential between the solid and solution phase (Telford and
others, 1990). Streaming potentials are generally of minor importance in mineral exploration
surveys, but can be found associated with large negative anomalies on topographic highs and are
important in spontaneous potential borehole logging where drilling fluids flow into porous
formations.
72.
-------
The diffusion potential is due to a difference between the concentrations of electrolytes and can
be expressed by the formula in millivolts (mV) (Telford et al./'1990):
Ed = - {R • 6 • (I. - Ic) • ln(Q / Q)} / {F • TI • (Ia + Ic)}
where R = the gas constant, 8.314xlQ-3 ia-°Cl-tK
F = Faraday's constant, 96.445 kJ-V^-mor1
9 = absolute temperature, °K
T| = ion valence
Ia = mobility of anions, m-s'W-nr1
I,. = mobility of cations, m-s'W-nr1
Q, Q = concentration of electrolytes
The Nerst potential occurs when the electrolyte concentrations around two identical metal
electrodes are different. The potential can be expressed in millivolts (Telford and others, 1990)
by:
En = - {R • 6 • ln(Q / Q) }/ {F • r\}
Where the coefficients are the same as above.
For example a NaCl solution where Ia / Ij = 1.49 produces a diffusion potential at 25 °C of
Ed - -11.6 • log (Q / C2) and a Nerst potential of En = -59.1 • log(Q / Q) (Telford and
others, 1990).
The electrochemical self potential is the sum of the diffusion and Nerst potentials and can be
expressed in millivolts as:
Ec . - 70.7 • [(T + 273)/273) • log(Q / Q)
where: T = temperature, °K
Mineralization potential, or sulfide potential, occurs when two dissimilar metal electrodes are
immersed in a homogeneous electrolyte. This potential is commonly found with ores containing
73.
-------
pyrite and chalcopyrite. Although the exact mechanism for large negative anomalies over sulfide
ores is not \fully understood, the use of self-potential surveys to locate ore bodies is a common
practice in mineral exploration. The combined effect of the diffusion and Nerst and
mineralization potentials is thought to be the principle cause of the large anomalies found with
certain mineral ores. Theories on the causes for self potential voltages associated with mineral
deposits are discussed by Sato and Mooney (1960), Kilty (1984), Cony (1985), and Fumess (1992
and 1993). Theories on causes for self-potential voltages associated with geothermal systems are
discussed by Corwin and Hoover (1979) and Sill (1983).
USE OF SP IN AMD INVESTIGATIONS
The use of self potential methods for investigating AMD problems is limited to areas where there
is sufficient ground-water flow to develop streaming potential anomalies because the diffusion,
Nerst and mineralization potentials are all reduced significantly by high specific conductance
electrolytes (Bogoslovsky and Ogilvy 1973,1972; and Ogilvy, Ayed and Bogoslovsky, 1969). A
review of literature found only two published reports on the use of SP for evaluating acidic fluids
(Stierman, 1984; and Reznik, 1990). The results of the Stierman study at an acid waste disposal
pond were too noisy to provide any definitive results. Reznik's (1990) study at a partially
reclaimed coal mine had better results. Reznik was able to identify ground-water flow direction
and sources of AMD seepage. Even though the application is limited SP can be useful in AMD
investigations because it can: 1) identify zones of increased infiltration; 2) identify areas of
leakage or seepage from canals, dams, springs and reservoirs; 3) evaluate effectiveness of ground-
water drainage structures; and 4) evaluate effects of ground-water pumping.
Studies of SP phenomena related to infiltration have been reported by Ernstson and Scherer
(1986), Bogoslovsky and Ogilvy (1970,1972,1973), and Erchul (1986). In general, infiltration of
surface water into fractured rock or karst sink holes produces SP minimum when compared to
the surrounding lands. This reduction in SP voltage is thought to be linearly related to the
pressure gradient as long as the flow is laminar and not turbulent (Ogilvy, Ayed and Bogoslovsky,
1969). Widening of fractures tends to decrease amplitude of the negative anomaly. Infilling of
fractures with sand up to approximately 40 percent causes the negative SP anomaly to increase.
Infilling with clay decreases the amplitude of the anomaly.
74.
-------
Studies of SP anomalies associated with canal, dam and reservoir leakage have been reported by
Ernstson and Scherer (1986), Ogilvy and Bogoslovsky (1979), JBogoslovsky and Ogilvy (1972), and
Ogilvy, Ayed and Bogoslovsky (1969). These studies found that a negative SP anomaly is
generally associated with areas of seepage with the intensity of the anomaly increasing at higher
rates of seepage.
Bogoslovsky and Ogilvy (1973) found that for subsurface drains, positive SP anomaly
equipotential lines parallel the discharge into the drain and negative anomalies are often
associated with the drain outlet. Bogoslovsky and Ogilvy (1973) used a SP survey to qualitatively
evaluate the effectiveness of a drainage system installed to dewater a landslide. The SP survey
found an increase in SP values adjacent to a section of the slide that continued to fail, suggesting
that the drain was not functioning.
Schiavone and Quarto (1984) found that SP anomalies can be associated with upward flow of
fresh water across geologic discontinuities or lithologic boundaries. Asymmetrical anomalies are
often associated with vertical boundaries while symmetrical anomalies occur over horizontal
boundaries (Schiavone and Quarto, 1984; and Fitterman, 1979). Radial flow to a pumping well
can produce a circular positive anomaly and injection of water a negative anomaly (Schiavone
and Quarto, 1984; and Bogoslovsky and Ogilvy, 1973).
Analysis of SP survey data is generally qualitative rather than quantitative because the SP
phenomena involve several different potentials, and because the exact nature of the
mineralization potential is still uncertain. Several authors have presented models for SP
interpretation of anomalies over vertical boundaries (Fitterman, 1979), vertical dikes (Fitterman,
1983), two-dimensional sheet-like and cylindrical sources (Satyanarayana Murty and Haricharan,
1985), spherical and elliptical ore bodies (Becker and Telford, 1965; and Telford and others,
1990), a thermal point source with vertical contact and overburden (Corwin and Hoover, 1979;
and Sill, 1983), current dipoles in half-space (Kilty, 1984), and surface and vertical profiles over
vertical and dipping sheet-like bodies (Furness, 1992).
Telford and others (1990) report the depth of an ore body is approximately one-half of the width
of the negative anomaly measured at half the amplitude, as a rule of thumb. Based on a limited
survey of SP studies, this rule, of thumb yields depths that are ±100 percent of the true depth.
Data from SP surveys are generally used as qualitative information along with other more
75.
-------
quantitative methods, such as D.C. resistivity and IP. Data are presented either as a plan map
with contours of SP voltages or as x-y plots of SP voltage versus distance along a traverse.
SP FIELD PROCEDURES
Field procedures for SP surveys use two electrode configurations: 1) two electrodes separated by
a constant distance are moved along a survey line, using a voltmeter to measure the gradient
between them, or 2) one electrode is placed as a base point and the other electrode is moved
from station to station using a long wire. The second method has an arbitrary referenced
"absolute" SP as a base point. The base point electrode is connected to the negative terminal of
the voltmeter. When the base point needs to be moved, the potential of the new base point is
measured relative to the previous base point so that data can be corrected to a fixed reference
voltage.
Detailed description of field procedures, precautions and instrument specifications are given by
Corwin (1990), Corwin and Hoover (1979), and Cony (1985). A summary of field procedures
and sources of noise is given below.
o Electrodes for the SP survey should be non-polarizing. Standard SP electrodes are
unglazed, porous porcelain pots with a metal terminal that is submerged in a salt solution
of similar composition, such as copper terminals in copper sulfate solution. The
permeable pot slowly leaks solution into the soil to make a good electrical contact with
the ground.
o Although porcelain electrodes are considered "non-polarizing" they do respond to such
factors as temperature, soil moisture, and soil chemistry. For example, for a copper-
sulfate electrode, changes in moisture content of 1 percent can cause a +0.3 to +1.0 mV
variation. Thus observation of soil moisture conditions can be critical when SP anomalies
are a few tens of millivolts (Corwin, 1990).
o Electrodes should be buried at least 6 inches for detailed surveys where the SP anomaly
has a low amplitude, such as over geothermal systems. Random noise of sufficient
amplitude to mask the anomaly is caused by moisture differences.
o For detailed low amplitude SP anomaly surveys, the ground surrounding the electrodes
should not be wetted and the contact resistance should be less than 50 k H. Voltage
should be read before contact resistance because the ohm-meter will temporarily polarize
the electrode. "
76.
-------
o Temperature variations between the electrodes should be kept to a minimum to reduce
voltage drift which can range from +0.5 to +1.0 mV per degree Centigrade.
o A high impedance (> 1 x 107 ohm-meters) digital voltage meter should be used for field
readings. The negative terminal of the voltmeter should be connected to the base station.
o Base station electrode should be placed outside an area of steep SP gradients for
maximum anomaly amplitude.
o Base station electrode should be placed outside a chemically reduced environment such as
a bog or marsh for maximum anomaly amplitude.
o Power stations, pipelines with cathodic protection, culverts, grounded fences, drill-hole
casings- and buried metallic objects should be avoided.
o Read differences between the electrodes at least at the beginning and at the end of the
survey to allow for correction of drift. At the beginning of the survey the difference
should be less than 2 mV. If greater, the electrodes should be cleaned and filled with
fresh electrolyte.
o Long period telluric currents caused by temporal variation in the earth's magnetic field
can be several hundred mV/km, and can increase the noise for a survey more than 1 km
long.
o Vegetated areas should be avoided because bioelectrical activity can generate SP
anomalies as high as 150 mV/m.
SEISMIC GEOPHYSICAL METHODS13
Seismic geophysical methods for subsurface investigations are divided into two categories,
refraction and reflection. These methods differ in the progression of seismic energy through the
earth's layers, and in data collection and interpretation. For shallow engineering, environmental
and hydrogeologic investigations, the seismic reflection method is not commonly used. A brief
discussion of seismic reflection applied to environmental and hydrogeologic investigations and a
limited reference list are presented at the end of this section. The following discussion is a brief
review of seismic refraction methods as applied to AMD, environmental and hydrogeologic
problems. Haeni (1988) provides a more detailed discussion of seismic refraction applications to
hydrologic studies including an extensive annotated bibliography.
References begin on page 130.
77.
-------
Seismic energy travels through the ground as four types of waves: 1) a compressional or
longitudinal wave (ground motion parallel to the direction of propagation); 2) a shear or
transverse wave (ground motion perpendicular to the direction of propagation); 3) a Rayleigh
wave (travels along the surface); and 4) a Love wave (travels along the surface). For engineering,
environmental, and hydrogeologic seismic surveys, the compressionalwave is utilized most often.
The shear wave is used for special engineering studies. Surface waves are not used.
Compressional waves travel the fastest, thus they are the first to arrive at the geophones and are
the easiest to identify on the seismographic record.
Figure 6 shows schematically the ray-paths of energy from a surface source for a two-layer earth
model. The two-layer earth model assumes ideal horizontal, homogeneous, and isotropic layers,
and velocity increasing with each deeper layer. Seismic waves travel outward from the energy
source along four ray-paths:
o as a direct ray-path along the surface;
o as a totally reflected ray-path that strikes the interface between two layers at an
angle greater than a critical angle of incidence (i,.), with all of the energy reflected
toward the surface at the velocity of the upper layer (Vx);
o at a critical angle of incidence (ic) where part of the energy is reflected at velocity
Y! and part of the energy is refracted along the interface between the two layers
at the velocity of the deeper layer (V2); and
o as a ray-path that strikes the interface at an angle less than the critical angle
where part of the energy is reflected and part is refracted downward into the
deeper layer.
The seismic refraction method uses the first and third ray-path properties and the critical angle of
incidence to develop formulas for calculating layer velocity and thickness. The critical angle of
incidence at the interface of two layers is given by:
ic = arcsin(Vi / V2)
where: Vj = the velocity of the upper layer
V2 = the velocity of the lower layer
78.
-------
ENERGY SOURCE
S
GEOPHONE
G
/-•-RAY PATH OF HEAD WAVE
"l >'c>'|
(3) PATH OF RAY REFRACTED
AlONG V, -VjCONTACT
Figure 6. Schematic ray-path diagram for seismic energy generated at source S and received
at geophone G (from Zohdy and others, 1974).
• Shotpoiml
Shotpoim 2
1 2 3 4 E 6
/™™ snotpoint 3 ^
/7 t 9 10 VI 12 /
Shotpoint 4 Shotpoint C
X
K
Q.
LU
!V VY| \~7T//! A '
\ \~* F ~ ~ ~ "V //
\ y / /
V / *- •— — ~ MM*"!"''
Layer 1
Layer 2
Layer 3
DISTANCE
Figure 7. Field setup of shotpoints and geophones for delineation of multiple-refracting
horizons. Only selected raypaths for shotpoint 1, 2 and 3 are shown. The
raypaths for shotpoints 4 and 5 are the mirror image (with respect to shotpoint 3)
of the raypaths for shotpoints 2 and 1, respectively (from Haeni, 1988).
79.
-------
Formulas for solving problems involving more than two layers have been developed from this
relationship and other geometric properties (Mooney, 1984; Haeni, 1988; and Crice, 1992).
Refraction interpretation formula assumptions are: 1) layer boundaries are planar and have a
uniform slope; 2) the land surface is flat; 3) all layers are seismically homogeneous and isotropic;
and 4) seismic velocity increases with depth. Formulas for three-layer problems can be readily
solved by hand or with hand-held calculators (Ballantyne and others, 1981). More complex
formulas are solved using computers (Hunter, 1981; Mooney, 1984; and Orndorff and others,
1989).
Seismic refraction surveys are usually conducted by placing a cable and geophones along a linear
trend at regular spacings. To maximize information, energy is sent into the ground from several
locations along the geophone spread and off-end. A typical layout of a seismic refraction line is
shown in Figure 7. The seismic wave sensed at each geophone is recorded on a seismograph
either as an analog or digital signal. The array of geophones is physically or electronically moved
along the line to obtain additional seismic profiles. The spacing of the geophones is determined
in part by the depth of interest, the thickness of the layers and the size of the target. There
should be at least two data points for each layer of interest to avoid ambiguities in interpretation.
Refraction cables commonly have takeouts for connecting the geophones at 25-, 50- and 100-foot
increments. Actual spacing can be adjusted by leaving slack in the cable between geophones.
For compressional wave seismic refraction surveys, the time of the arrival of the first compression
wave is selected for each geophone from the recording. To enhance the signal from a low energy
source and to reduce the effect of noise, most modem seismographs allow stacking of repeated
shots. Variations in the subsurface geology will cause the arrival times at the geophones to differ
and plots of the distance versus first-arrival time will be non-symmetrical. Interpretations of the
layer dip, thickness, velocity and material types are based on these variations as seen in the time-
distance plots.
Interpretation of refraction data is done by plotting the first arrival times for each geophone on
the vertical axis at their distance from the shot point (energy source) on the horizontal axis as
shown in Figure 8. Straight lines are drawn through points thought to represent first arrivals at a
single layer. The slope of a line is the inverse of the velocity of the layer it represents. Depth to
a layer interface is calculated based on either: 1) a crossover distance (XQ,, or x^) at which the
refracted wave traveling along the layer interface reaches the geophone faster than the direct
80.
-------
wave; or 2) by projecting each segment to zero distance and using the zero intercept time (t2u, or
tM). The crossover distance for each interface is found at the-break in slope as shown of Figure
8. The intercept times and the crossover distances are directly dependent on the thickness and
the compressional velocity of the each layer. A detailed discussion of seismic refraction theory,
field methods,' and interpretation is given by Mooney (1984) and Haeni (1988).
An alternative method for interpreting seismic refraction data that give a depth and velocity
profile beneath each geophone is the generalized reciprocal method (GRM). GRM
interpretation calculates velocity analysis and time-depth functions to define continuous forward
and reverse direction profiles using the technique of phantoming (Palmer, 1980 and 1981;
Lankston and Lankston, 1986; and Lankston, 1990). The computed values for the velocity
analysis and the time-depth functions are referenced to a position, termed the G-position, which
lies half-way between two geophones separated by a distance XY. Multiple calculations are done
for various XY distances to generate values of the velocity analysis and time-depth functions
versus G-position, creating a suite of curves. Based on a subjective criteria of either minimal
curve irregularity for the velocity analysis function or maximum curve irregularity for time-depth
function, an optimum XY spacing is selected. The time-depth function curve for the optimum
XY spacing is then used to calculate the depth to the target refractor surface at each G-position.
The closer the geophones are spaced the more detailed the information on the refractor surface.
When an optimal XY distance can be determined with confidence, GRM can determine the
depth to the target refractor even when the velocity and thickness of the overlying layers are
unknown. GRM can also give an indication that undetected layers are present and indicate
whether they are hidden because of a velocity inversion or because they are too thin (Lankston,
1989 and 1990; and Palmer, 1980). The GRM requires many calculations, and computer
programs are available (Hatherly, 1976).
Special refraction and downhole survey are performed for additional information about the
dynamic properties of the subsurface layers, including shear velocity and shear modulus. The
geophones and energy sources differ from normal compressional surveys and digital recording of
the wave form is required to process the signal (Mooney, 1974; and Dobecki,1979).
81.
-------
Shotpoint
9 N. 10 11 12
DISTANCE
Figure 8.. Typical geophone and shotpoint layout with seismic raypaths and time-distance
plots for a two-layer model with a dipping boundary (from Haeni, 1988).
82.
-------
Because the material properties measured by seismic methods, primarily velocities of sound
waves, are ,not directly related to AMD geochemistry or conditions that generate AMD, the
application of shallow seismic refraction to AMD investigations is limited to general evaluations
of subsurface geology and hydrology. Knowledge about subsurface geology and hydrology can
complement and help calibrate other geophysical methods such as D;C. resistivity and
electromagnetics. Seismic refraction and perhaps reflection surveys can:
o provide complementary data for calibration of other geophysical surveys;
o delineate depth and lateral extent of waste fills;
o define and locate geologic structures such as faults and formation contacts;
o identify gravel channels within finer grained materials;
o define water table in unconsolidated sediments;
o identify subsurface voids; and
o azimuth refraction surveys can be used to measure anisotropy in fractured rock
and in some cases determine the main direction of vertical fracturing.
Papers that describe the use of seismic refraction methods in environmental and hydrogeologic
investigations include: Burke (1967), Eaton and Watkins (1967), Lennox and Carlson (1967),
Bruehl (1983), Kopsick and Sanders (1983), Taylor and Cherkauer (1984), Underwood and others
(1984), Haeni (1988), King and others (1989), Barker (1990), Lankston (1990), Steeples and
Miller (1990), Carpenter and others (1991), Cooksley (1992), Crice (1992), and Davies and others
(1992).
Although reflection methods are generally not applied to shallow environmental or hydrogeologic
investigations, some research has been reported by Muir and Higgins (1990), Davies and King
(1992), Davies and others (1992), King (1992), Hill (1992), and Brabham and McDonald (1992).
83.
-------
GRAVITY GEOPHYSICAL METHODS14
\
Measurement of the earth's gravitational field at the surface are compared to an arbitrary datum
to learn about subsurface structures. Predictable differences in the earth's gravitational field are
caused by changes in elevation and latitude, diurnal tidal distortion, and lateral variations in rock
bulk density. The standard cgs unit for the earth's gravitational acceleration is approximately 980
cm/sec2 or 980 Gals (Galileos) = Ig (gravity), and 1 Gal = 1 cm/sec2 = 0.0010197 g. The units
of gravitational acceleration commonly used in land gravity surveys is milligals (mGals). One
milligal is one-thousandth of a Gal = 1 x IQr6 g. Gravity meters can detect variations in the
earth's gravitational field as small as a few hundredths of a milliGal or better. For example, the
LaCoste and Romberg Model D microgravity meters are precise to 0.001 mGal (1 x 10"9 g). In
order to identify small geologic changes, field data must be corrected, to account for variations in
elevation, latitude, terrain, tidal effects and instrument drift (Telford and others, 1990).
Free-air and Bouguer elevation corrections must be applied to field data. The free-air correction
adjusts for the difference in distance from the center of the earth to the datum plane and to the
station. The datum plane is usually sea level but adjustments can be made to any datum. The
adjustment is the addition of 0.09406 mGal per foot (03086 mGal/m) of elevation above the sea
level datum. The adjustment is made regardless of whether or not there is rock material between
the sea level datum and the station, hence the term free-air correction. The Bouguer correction
removes the effect of the gravitational attraction caused by an assumed infinite slab of material
between the horizontal plane of each station and the datum. The Bouguer correction assumes an
infinite slab of material of bulk density pb with a base at the datum (sea level) and the top at the
station elevation. A Bouguer correction of 0.01278-pb mGal/ft (0.04192-pb mGal/m) is subtracted
from the field data, assuming a sea level datum (Telford and others, 1990).
Field data must be corrected for latitude because the earth is not a true sphere, but an ellipsoid.
The latitude correction is subtracted from the free-air and Bouguer corrected data and is given
by the formula (Telford and others, 1990):
g = 978031.846 • [1 + 0.005278895 • sin2() + 0.000023462 • sin4(<|>)]
^Reference begin on page 133.
84.
-------
where: g = acceleration of gravity, mGals
<(> = the latitude of station in degrees
The terrain correction adjusts for the effects of topographic variations in the vicinity of the data
station. Hills nearby the station give an upward component of gravitational attraction that
counteracts a portion of the downward pull of the earth. Valleys nearby have the effect of
causing a smaller downward pull at the station than is accounted for by the Bouguer correction.
The terrain correction is begun by centering a template over the station and estimating the
average elevation within each area delineated by radial lines and concentric circles. The terrain
correction factor is the elevation difference between the station and each compartment, and is
calculating the gravitational effect represented by each compartment. The total terrain correction
factor is added to the gravity value at each station (Dobrin, 1976; and Telford and others, 1990).
If a high precision gravity survey is required, correction for the effects of tidal changes and
instrument drift must be made. Periodic readings at one station are necessary to estimate the
magnitude of the drift and adjust the data accordingly. Earth's tide can cause as much as 0.3
mGal cyclic changes in gravity at any one point (Telford and others, 1990).
The correction of the field data for free-air, Bouguer, and latitude is termed the Simple Bouguer
Anomaly. The inclusion of the terrain correction is called the Complete Bouguer Anomaly.
One of the main problems with interpretation of gravity data is the need to remove the effects of
other features, such as regional gradients, that are superimposed onto the signature of the
anomaly of interest. Several methods that have been used to extract the anomaly of interest
include the following methods (Telford and others, 1990):
o The trend surface method assumes that regional gravitational effects can be modeled by a
simple low-order polynomial surface such as a plane. The trend surface is then
subtracted from the observed data and a map of gravity residuals results. The concept is
that the removal of the regional data will enhance the trends caused by the local
anomalies. In some cases where data are noisy, a high-order polynomial surface is fit to
the observed data before subtracting out the low-order regional surface. Drawbacks to
the method include that the regional effects may not be accurately represented by a
simple surface and that the use of high-order polynomials to fit the field data can
introduce anomalies that are due solely to the fitting processes.
85.
-------
o A spatial frequency filtering method uses band-pass filters to isolate spatial frequency
components caused by shallow or deep density changes, This method requires some
knowledge of the wavelength of the feature being investigated. The apparent wavelength
of the anomaly is roughly proportional to the depth of the lateral density change causing
the anomaly. A shallow mass or near-surface noise causes a short wavelength anomaly
while deep regional mass causes a broad wavelength anomaly.
o The forward modeling method computes an ideal gravitational simulation that should be
caused by the feature being investigated. Results of the simulated model are then
compared with the actual data. Repeat simulations and comparisons are made until an
acceptable fit is found.
o The graphical method produces a smoothed surface that does not contain local anomalies
and then this surface is subtracted from the original data to produce a map of residuals
representing the local anomalies.
o The gridding method is used to predict the regional gradient by averaging the Values
within a specific radius of a station. The radius is on the same order of magnitude as the
depth of the anomaly of interest.
o The second derivative method uses a grid to calculate the second derivative at a station
from a weighted average of surrounding stations. The second derivative method measures
the curvature of the gravity field and is most influenced by shallow anomalies.
For environmental and engineering studies where the targets are generally small shallow features,
high-precision microgravity surveys are done. Microgravity studies of small areas require precise
instrument readings and gravity station location. A precision of 10 centimeters in elevation and
30 meters in latitude (0.03 mGal accuracy) with grid spacings of a few meters is commonly
needed (Telford and others, 1990). Environmental surveys of small areas generally assume that
the regional gradient is a simple sloping plane or curve, like most geophysical methods,
interpretation of gravity data is non-unique and the interpreter must use all available data to limit
the solutions.
Application of gravity surveys in AMD investigations would include: delineating waste pile
dimensions, especially for deep canyon fills; and identifying voids, tunnels and subsurface mine
workings. Reports and papers on the use of gravity surveys for environmental, engineering and
hydrogeologic studies include: Dean (1958), Eaton and Watkins (1967); Lennox and Carlson
(1967); Arzi (1975), Ibrahim and Hinze (1972), Zohdy and others (1974), Carmichael and Henry
(1977), Butler (1984), Dahlstrand (1985), Roberts (1989), Roberts and others (1989), Hinze
(1988), Kick (1989), Adams and Hinze (1990), Hart and Muir (1990), Richard and Wolfe (1990),
Sandberg and Hall (1990), Wolfe and Richard (1990), West (1992), and Kelly and Mares (1993).
86.
-------
MAGNETIC GEOPHYSICAL METHODS15
Land based magnetic surveys measure the variations in the earth's magnetic field caused by near-
surface ferrous materials to locate buried targets. The earth's total magnetic field intensity is not
uniform because of the dipoler nature of magnetism and because of the distribution in the earth
of rocks having differing magnetic properties. The sun and solar flares temporarily distort the
earth's magnetic field.
Diurnal variations occur during daylight hours although their timing and magnitude are not
totally predictable (Telford and others, 1990). They usually must be removed from total field
intensity data because their magnitude of tens of gammas can obscure anomalies of interest.
During field surveys that last several hours, a recording base station or periodic recording at the
same point is needed in order to record the diurnal variation.
Modern magnetic instruments usually measure the total magnetic field intensity. An alternative
method is the vertical gradient magnetometer survey. This method measures the magnetic field
at two pomts vertically separated by approximately 1 meter with the gradient being the change in
magnetism between sensors. While the total magnetic field for the earth varies throughout the
day, the gradient between these two vertically separated points should be relatively constant.
Thus there is no need to correct for diurnal variations, and repeat surveys should give similar
data.
The magnetometer survey is generally carried out along a linear traverse or a grid. Data
corrected for diurnal effects and sometimes smoothed are generally analyzed qualitatively by
contouring or plotting a profile. Quantitative interpretation can be done (Telford and others,
1990), but usually the buried metal objects of interest in environmental work do not lend
themselves to simple geometric models.
While there are several types of instruments used for measuring the earth's magnetic field, the
proton-precession magnetometer is the most common in environmental and engineering studies
(Breiner, 1973 and 1992; and Telford and others, 1990). The proton-precession magnetometer
can read the total magnetic field to a sensitivity of 0.1 gamma. The total intensity of the earth's
References begin on page 135.
87.
-------
magnetic field in the contiguous United States ranges from 50,000 to 60,000 nanoteslas (1
nanotesla ^ 1 gamma = 10'5 gauss = 105 oersted = 10"9 web'ers/m2 = 10'9 tesla).
Magnetometer surveys can be of use in AMD investigations because they allow for rapid
identification o'f shallow buried ferrous objects, common to mine sites. Magnetometer surveys
can also aid in distinguishing between a conductive soil/rock mass from buried ferrous metal as
being the source of an electromagnetic, low resistivity anomaly. For this reason, magnetometer
surveys are commonly done for quality control in electromagnetic and resistivity surveys.
Details on the theory and application of proton-precession magnetometers can be found in
Breiner (1973 and 1992) and Telford and others (1990), as well as general geophysical textbooks
(see list of general references). Discussions of survey methods and interpretation for
environmental problems are given by Zohdy and others (1974), Fowler and Pasicznyk (1985),
Hinze (1988), Allen and Rogers (1989), and DeReamer and Pierce (1990).
GROUND PENETRATING RADAR METHOD16
In recent years the increased demand in the environmental studies for detailed knowledge about
the shallow subsurface and of objects buried within the upper 15 to 30 feet has led to the
development of a ground-based, high frequency, electromagnetic geophysical instrument known
as ground penetrating radar (GPR). This geophysical instrument employs a short duration,
electromagnetic pulse using a broad-bandwidth antenna placed directly on the ground. The
depth of penetration and resolution are controlled by the antenna frequency which commonly
ranges from 80 Hz to 1000 Hz. GPR detects differences in the dielectric properties of buried
materials. Voids and buried objects such as barrels and sewer lines have sufficiently different
dielectric properties to be detected.
GPR has advantages over other geophysical methods in that: 1) it can detect changes in the
dielectric properties of material that may not be apparent to magnetic or resistivity geophysical
methods; 2) it has the highest target resolution of any shallow depth geophysical method; 3) a
survey can be done as rapidly as the operator can walk it; 4) output is a real-time plot and does
6References begin on page 136.
-------
not require correction or processing; and 5) real-time graphic output allows rapid interpretation
and modification of survey.
GPR limitations include: 1) survey results are site dependent; 2) an increase in moisture content
of soils can reduce the signal, and ground water absorbs the signal; 3) an increase in clay content
reduces the signal; 4) penetration and resolution are frequency dependent; 5) the antenna must
pass near the object to detect it.
GPR surveys are typically conducted along a grid or a linear traverse across an area of interest.
Grid size varies with the target size (see previous section on line spacing and probability, page
24). Preliminary surveys are needed to calibrate the instrument to site conditions.
GPR can be applied to AMD investigations where shallow buried objects are of interest and
contrasts in the dielectric properties of materials or voids are assumed. These types of
investigations might include locating buried barrels, pipelines, old disposal trenches, and shallow
voids. A drawback to the use of GPR is the radar antenna must be in direct contact with the
ground to develop an adequate return signal. An irregular surface common at mine sites will
significantly affect the results.
Review of GPR theory and methods for environmental studies is given by: Morley, (1974), Cook
(1975), Coon and others (1981), Benson and others (1984), Davis and others (1984), Wright and
others (1984), Underwood and Bales (1984), Olhoeft (1988), Boucher and Galinovsky (1989),
Davis and Annan (1989), Daniels (1989), Filler and Kuo (1989), Hennon (1990), Beres and
Haeni (1991), Fisher and others (1992), and Allen and Seelen (1992).
BOREHOLE GEOPHYSICAL METHODS17
Borehole geophysical or well logging includes all methods for lowering a sensing device down a
cased or uncased borehole to record physical, chemical, electrical, electromagnetic, or radioactive
parameters along the well bore. Borehole logging is used extensively by the petroleum and
minerals industries, and to a limited extent by the geotechnical and water resources industries. In
References begin on page 138.
89.
-------
recent years with the increase in the number environmental and hydrogeologic investigations
associated with ground-water pollution, borehole geophysics have become an important tool to
assist the geologist and hydrogeologist in interpreting subsurface geology and hydrology.
Papers that report extensive use of borehole geophysical methods in the study of AMD problems
or in the monitoring of AMD were not found in the literature search. Nevertheless, there are
numerous studies of high specific conductance ground-water pollution that utilized borehole
geophysics. These studies clearly indicate that borehole geophysics can have direct application to
AMD investigations and to long-term monitoring of AMD pollution. There are numerous
borehole geophysical methods and many variations on each method developed for special
applications. The purpose of this summary is not to cover the topic in detail, but to provide a
general overview of the available methods and references for more detailed research. Therefore,
the following is a brief discussion of the methods of borehole geophysics as might be applied to
the investigation of AMD.
The types of borehole geophysical logging devices are numerous but can be generally divided into
the following five groups based on the parameter measured:
o Electrical resistivity and conductivity;
o Nuclear,
o Acoustic;
o Borehole fluid; and
o Well construction.
Electrical resistivity or conductivity logging tools are designed to measure formation and
formation water resistance using a variety of designs and electrode configurations. These
methods generally are done in an open hole although some of the electromagnetic induction
tools can penetrate non-conductive well casing, such as plastic. The electrical methods are
accomplished by inducing current into the borehole wall and reading the response at one or more
electrodes. The electrical resistivity methods include: point resistivity, short normal, long
normal, lateral resistivity, focused resistivity, microlog, dipmeter, induced polarization, and
electromagnetic induction logs. This group should also include a special type of electrical log,
90.
-------
spontaneous potential, that measures natural potential differences caused by electrochemical
reactions between layers.
\
Nuclear logging commonly uses measurements of either the level of natural radioactive material
decaying in formations, or the level of backscatter or adsorption in the formation material caused
by a radioactive source within the logging tool. The characteristics of the formations are
determined by the amount of natural radioactivity or the response to radiation. An advantage of
radioactive logs is that they can be run in open or cased holes. Commonly used radioactive logs
include: natural gamma, gamma-gamma, neutron, spaced neutron, density, gamma spectrometry,
neutron-activation, pulsed-neutron-decay, and dual-detector-density logs.
Acoustic logging uses sound waves generated by the logging probe to measure formation
properties, primarily porosity, fracture density and orientation, and the quality of annular space
cementation. Acoustic methods include: sonic, tube wave amplitude, variable density, full
waveform sonic, borehole acoustic televiewer, and acoustic cement bond logs.
Borehole fluid logs measure the physical and chemical characteristics of the fluids in the borehole
and the adjacent formation and include: fluid conductivity, brine injector-detector, radioactive
tracerjector, Eh, pH, temperature and differential-temperature, impeller-type flowmeter, and
heat-pulse flowmeter logs. These logs must be run in an open hole that has ground water in
equilibrium with the formation water.
The final group are well-construction logs: downhole video camera, casing-collar indicator,
directional survey and caliper. These are run as part of the engineering design of the well or
following well completion to document the construction.
Interpretation of borehole logs can be done qualitatively or quantitatively. Most quantitative
methods were developed by the petroleum and minerals industries. Numerous books are
available on well log interpretation and include: Lynch (1962), Schlumberger (1972a, 1972b,
1974, 1977), Dresser Atlas (1975), Merkel (1979), Hearst and Nelson (1985), Labo (1986), and
Brock (1986).
. Several papers that discuss the principles, applications and interpretation of borehole geophysics
as it relates to environmental and fresh ground-water investigations are available and include:
91.
-------
Jones and Buford (1951), Keys (1967 and 1989), Keys and MacCary (1971), MacCary (1978),
Engineering Enterprises (1985), Driscoll (1987), Collier and Alger (1988), Stegner and Becker
(1988), Stowell (1989), Daniels and Keys (1990), Howard (1990b), Paillet and Saunders (1990),
Roscoe Moss Company (1990), Yearsley and Crowder (1990 and 1991), Crowder and others
(1991), Yearsley and others (1991), Yearsley and Crowder (1991), Mwenifumbo (1993), and
Welenco Inc. (undated).
Several authors address the use of borehole geophysical logs in determining subsurface
parameters of shallow formations and fresh-water aquifers. Parameters that are measured
include: lithology, porosity, permeability, bulk density, clay and shale content, moisture content,
ground water flow direction and velocity, and chemical dispersion. Papers on these subjects
include: Croft (1971), Barker and Worthington (1973), Griffiths (1976), Ogbe and Bassiouni
(1978), Biella and others (1983), Snelgrove and McNeill (1985), Spencer (1985), Huntley (1986),
Taylor and others (1989), Burns (1990), and Hess and Paillet (1990).
Correlation of borehole geophysical measurements and quality of shallow ground water is
discussed by numerous authors including: Turcan (1962 and 1966), Alger (1966), Moore (1966),
Desai and Moore (1969), Worthington and Barker (1972), Worthington (1976), Kwader (1985
and 1986), Guo (1986), Alger and Harrison (1988), and Jorgensen (1989 and 1990).
Studies on the use of borehole geophysical methods used to investigate fracture zones, fracture
density, orientation, and transmissivity are given by: Deluca and Buckley (1985), Morin and
others (1988), Merin (1989), and Howard (1990a).
Figure 9 is a matrix listing most of the geophysical logs commonly used in environmental and
ground-water investigations along with the applicability of each method to various geologic and
hydrologic studies (Keys and MacCary, 1971; Welenco, undated). Figure 9 indicates whether the
logging method can be used with open or cased holes.
Application of borehole geophysical logs to the investigation of AMD is similar to the application
to other environmental investigations. Applications include: aid in identifying and correlating
subsurface geologic units, determining physical parameters such as hydraulic conductivity,
. determining water quality, evaluating the interconnection of aquifers, and determining the
effectiveness of ground-water cleanup programs. An additional use of borehole logging for AMD
92.
-------
investigations is the use of conductivity logs to map the extent and change in high specific
conductance ground-water pollution. For example, electromagnetic induction tools, such as the
Geonic's EM39, can be run down wells with non-metal casings to measure the conductivity of the
formation fluids. Thus periodic logging of the well can monitor the appearance and extent of an
AMD plume.
93.
-------
NOIIVNIIONI 31OH
NOI1VOOT HSId
SNOIlVlMUOd dO
lOaiNOO HJLd3Q
aaiawviaa-ioH
ONioomd ao
sxvan ONISVO
Noisoaaoo ONISVO
NOiionaisNOO TBM
ONUN3W3O
T13M Nl a31VM dO
jjMawaAovN * aoanos
Momma
Noiiaadsia
AJJOOTaA^OLLoiaiS
NonvanidNi
iNaiNOO aanisiow
sauaadoadivoi
-SAHdSTVOIINaHO
3navj.usj.VM
A1ISN3Q X1HQ
AllSOaOd 3ALLO3dd3
Aiisoaodnvioi
aivHslA^RS
ssaNxoiHioae
AOOIOHir
NOiivnaaaoc
-
O
0
o
1 O
> o
•
o
o
0
0
o
o
o
o
o
o
o
o
o
o
o
o
1
0
o
o
•
o
o
o
0
0
0
D«
•
•
•
•
•
•
•
•
0«
Oi
Oi
0«
•
0«
09
o*
o«
Oi
lOi
»0i
>OI
o*
0«
o
Oi
Oi
o
Oi
Oi
•
•
0«
Oi
>Oi
>
•
0
>
> Oi
OI
•
•
o«
•
o*
•
o
o
0
o
0
o
o
o
o
•
•
O9
(
•
•
D«
•
•'
•
•
•
0*
o
o
o
0
•
o
s 1 * * ! 1 o § § 8 o ii i 1 i 1 i f
fe H 1 5 8 1 ! 3 | j i ! P i 3 1 § 3 ! i
^z»-z-lhoOj}JS(ruja:t0ui£tj|2^^<-^
zfiecooXerOfiilHoHcoso.u.SS^QfJ.a
Figure 9. Matrix of applicability of borehole geophysical methods commonly used in
engineering and environmental investigations. Open circle = open hole; filled
circle = cased hole. Casing material for EM methods must be non-conductive
such as plastic, (modified after Welenco, undated; and Keys and MacCary, 1971)
94.
-------
IV. REFERENCES
GEOPHYSICAL TEXTBOOKS
Bhattacharyya, P. and Patra, H., 1968, Direct Current Geoelectrical Soundings: Elsevier Press,
. Amsterdam, the Netherlands, 135 p.
Dobrin, M.B., 1976, Introduction to Geophysical Prospecting (Third Edition): McGraw-Hill
Book Company, New York, New York, 630 p.
Griffiths, D.R, and King, R.F., 1981, Applied Geophysics for Geologists and Engineers (Second
Edition): Pergamon Press, New York, New York, 230 p.
Hearst, J.R., and Nelson, P.W., 1985, Well Logging of Physical Properties: McGraw-Hill, New
York, New York, 571 p.
Keller, G.V., and Frischknecht, F.C., 1966, Electrical Methods in Geophysical Prospecting:
Pergamon Press, New York, New York, 523 p.
Labo, J., 1986, A practical Introduction to Borehole Geophysics, Geophysical References,
Volume 2: Society of Exploration Geophysicists, Tulsa, Oklahoma, 330 p.
LeRoy, L.W., and LeRoy, D.O., 1977, Subsurface Geology, Petroleum, Mining, Construction:
Colorado School of Mines, Golden, Colorado, 941 p.
Lynch, EJ., 1962, Formation Evaluation: Harper and Row, Publishers, New York, New York, 422
P-
Milsom, J., 1989, Field Geophysics-Geological Society of London Handbook: Halsted Press, John
Wiley and Sons, New York, New York, 182 p.
Nabighian, M. K, editor, 1988 (Volume 1-Theory), 1990 (Volume 2-Applications),
Electromagnetic Methods in Applied Geophysics: Society of Exploration Geophysicists,
Tulsa, Oklahoma.
Parasnis, D.S., 1973, Mining Geophysics, 2nd Edition: Elsevier, New York, New York, 395 p.
Parasnis, D.S., 1986, Principles of Applied Geophysics (Fourth Edition): Chapman Hall, New
York, New York, 402 p.
Robinson, E.S., and Coruh, C, 1988, Basic Exploration Geophysics: John Wiley & Sons, New
York, New York, 562 p.
Sharma, P.V., 1986, Geophysical Methods in Geology (Second Edition): Elsevier Science
Publishing Co., New York, New York, 442 p.
95.
-------
Sumner, J.S., 1976, Principles of Induced Polarization for Geophysical Exploration, Developments
in Economic Geology, No. 5: Elsevier Science, Amsterdam, the Netherlands, 277 p.
Telford, W.M., Geldart, L.P. and Sheriff, R.E., 1976, Applied Geophysics: Cambridge University
Press, New York, New York, 770 p.
Telford, W.M., Geldart, L.P. and Sheriff, R.E., 1990, Applied Geophysics (Second Edition):
Cambridge University Press, New York, New York, 770 p.
96.
-------
REFERENCES ON
ENVIRONMENTAL, GROUNDWATER
and GEOTECHNICAL GEOPHYSICAL METHODS
Association of Engineering Geologist, Sacramento Section, 1990, Geophysical Applications in
Engineering Geology and Ground Water, 3rd Annual Seminar Proceeding, June 15-16,
1990, Sacramento, California.
Benson, R.C., Turner, M, and Vogelson, W., 1988, In Situ, Time Series Measurements for Long
Term Ground-Water Monitoring, in A.G. Collins and A.I. Johnson, editors, Ground-
Water Contamination, Field Methods, ASTM STP-963: American Society for Testing and
Materials, Philadelphia, Pennsylvania, p. 58-72.
Benson, R.C., Turner, M.S., Volgelson, W.D., and Turner, P.P., 1985, Correlation Between Field
Geophysical Measurements and Laboratory Water Sample Analysis, in Proceedings of
NWWA Conference on Surface and Borehole Geophysical Methods in Ground Water
Investigation, February 12-14, 1985, Fort Worth, Texas: National Water Well
Association, Worthington, Ohio, p. 178-197.
Boulding, J.R., 1992, Use of Airborne, Surface and Borehole Geophysics at Contaminated Sites,
EPA/625/R-92/007: U.S. Enviornmental Protection Agency, Office of Research and
Development, Cincinnati.
Boulding, J.R., 1993, Subsurface Characterization and Monitoring Techniques-A Desk Reference
Guide, Volume 1, Solids and Ground Water, EPA/625/R-93/003A: U.S. Enviornmental
Protection Agency, Office of Research and Development, Cincinnati.
Boulding, J.R., 1993, Subsurface Characterization and Monitoring Techniques-A Desk Reference
Guide, Volume 2, The Vadose Zone, EPA/625/R-93/003B: U.S. Enviornmental Protection
Agency, Office of Research and Development, Cincinnati.
Bruehl, D.H., 1983, Use of Geophysical Techniques to Delineate Ground-Water Contamination,
in Proceeding of the Third National Symposium on Aquifer Restoration and Ground-
Water Monitoring, May 25-26,1983, Fawcett Center, Columbus, Ohio: National Water
Well Association, Worthington, Ohio, p. 295-300.
Glaccum, R.A., Benson, R.C., and Noel, M.R., 1982, Improving Accuracy and Cost Effectiveness
of Hazardous Waste Site Investigations: Ground Water Monitoring Review, Summer
1982, p. 36-40.
Greenhouse, J.P., Monier-Williams, M., 1985, Geophysical Monitoring of Ground Water
Contamination Around Waste Disposal Sites: Ground Water Monitoring Review, Fall
1985, p. 63-69.
Greenhouse, J.P., and Slaine, D.D., 1986, Geophysical Modelling and Mapping of Contaminated
Groundwater Around Three Waste Disposal Sites in Ontario: Canadian Geotechnical
Journal, v. 23, ho. 3, p. 372-384.
97.
-------
Griffiths, D.H., and King, R.F., 1981, Applied Geophysics for Geologists and Engineers (Second
Edition): Pergamon Press, New York, New York, 230 .p.
Hitchcock, A.S., and Harmon, H.D., Jr., 1983, Application of Geophysical Techniques as a Site
Screening Procedure at Hazardous Waste Sites, in Proceeding of the Third National
Symposium on Aquifer Restoration and Ground-Water Monitoring, May 25-26, 1983,
Fawcett Center, Columbus, Ohio: National Water Well Association, Worthington, Ohio,
p. 307-312.
Kelly, W.E., Bogardi, I. Nicklin, M., and Bardossy, A., 1988, Combining Surface Geolelectrics and
Geostatistics for Estimating the Degree and Extent of Ground-Water Pollution, in A.G.
Collins and A.I. Johnson, editors, Ground-Water Contamination: Field Methods, ASTM
STP-963: American Society for Testing and Materials, Philadelphia, Pennsylvania, p. 73-
85.-
Kelly, W.E., and Mares, S., editors, 1993, Applied Geophysics in Hydrogeological and •
Engineering Practice, in Developments in Water Science, v. 44: Elsevier Science
Publishers B.V., New York, New York, 289 p.
Keys, W.S., 1989, Borehole Geophysics Applied to Ground Water Investigations: National Water
Well Association, Dublin, Ohio, 313 p.
Keys, W.S., and MacCary, L.M., 1983, Application of Borehole Geophysics to Water Resource
Investigations: Techniques in Water-Resource Investigations of the U.S. Geological
Survey, Chapter El, Book 2,126 p.
Lewis, M.R., and Haeni, F.P., 1987, The Use of Surface Geophysical Techniques to Detect
Fractures in Bedrock-An Annotated Bibliography: U.S. Geologic Survey Circular 987, 14
P-
Lobo, J., 1986, A Practical Introduction to Borehole Geophysics, An Overview of Wireline Well
Logging Principles for Geophysics, Geophysical References Series Volume 2: Society of
Exploration Geophysicists, Tulsa, Oklahoma, 330 p.
Mazac, O., Kelly, W.E., and Landa, I., 1985, A Hydrogeophysical Model for Relations Between
Electrical and Hydraulic Properties of Aquifers: Journal of Hydrology, v. 79, p. 1-19.
Merkel, R.H., 1986, Well Log Formation Evaluation, AAPG Continuing Education Course Notes
Series No. 14: American Association of Petroleum Geologists, 82 p.
Mooney, H.M., 1980, Handbook of Engineering Geophysics, Volume 2, Electrical Resistivity:
Bison Instruments, Minneapolis, Minnesota.
Mooney, H.M., 1984, Handbook of Engineering Geophysics, Volume 1, Seismic: Bison
Instruments, Minneapolis, Minnesota.
Morley, L.W., 1967, editor, Mining and Groundwater Geophysics, Economic Geology Report No.
26, Geological'Survey of Canada, Proceedings of the Canadial Centennial Conference on
Mining and Groundwater Geophysics, Niagara Falls, Canada, October 1967: Department
of Energy, Mines and Resources, Ottawa, Canada, 722 p.
98.
-------
Orndorff, R.C., Dodd, K., Bunnells, G.B., and Sakss, Y, 1989, Computer Programs Released as
U.S. Geological Survey Publications Through August 1989: U.S. Geological Survey Open-
File Report 89-681, 70 p.
Paillet, F.L., and Saunders, W.R., editors, Geophysical Applications for Geotechnical
Investigations, ASTM STP-1101: American Society for Testing and Materials,
Philadelphia, Pennsylvania, 112 p.
Saunders, W.R., and Cox, S.A., 1988, Technical and Logistical Problems Associated with the
Implementation and Integration of Surface Geophysical Methods in Inactive Hazardous
Waste Site Investigations, in Proceedings of the Second National Outdoor Action
Conference on Aquifer Restoration, Ground Water Monitoring and Geophysical
Methods, Volume II, May 23-26,1988, Las Vegas, Nevada: Association of Ground Water
Scientists, Worthington, Ohio, p. 637-653.
Stierman, D J., and Ruedisili, L.C., 1988, Integrating Geophysical and Hydrogeological Data: An
Efficient Approach to Remedial Investigation of Contaminated Ground Water, in A.G.
Collins and A.I. Johnson, editors, Ground-Water Contamination: Field Methods, ASTM
STP-963: American Society for Testing and Materials, Philadelphia, Pennsylvania, p. 43-
57.
Tweeton, D.R., Cumerlato, C.L., Hanson, J.C., and Kuhlman, H.L., 1991, Field Tests of
Geophysical Techniques for Predicting and Monitoring Leach Solution Flow During In
Situ Mining: Geoexploration, v. 28, p. 251-268.
van Blaricom, R., compiler, 1992, Practical Geophysics II for the Exploration Geologist:
Northwest Mining Association, Spokane Washington, 570 p.
Ward, S.H., editor, 1990, Geotechnical and Environmental Geophysics, in Investigations in
Geophysics No. 5, Volume I, Review and Tutorial: Society of Exploration Geophysicists,
Tulsa, Oklahoma, 389 p.
Ward, S.H., editor, 1990, Geotechnical and Environmental Geophysics, at Investigations in
Geophysics No. 5, Volume II, Environmental and Groundwater: Society of Exploration
Geophysicists, Tulsa, Oklahoma, 343 p.
Ward, S.H., editor, 1990, Geotechnical and Environmental Geophysics, in Investigations in
Geophysics No. 5, Volume III, Geotechnical: Society of Exploration Geophysicists, Tulsa,
Oklahoma, 300 p.
Welenco, Inc., Water Well Geophysical Logs (Second Edition), Bakersfield, California, 81
P-
Welenco, Inc., Water Well Geophysical Logs (Third Edition), Bakersfield, California, 59
P-
Zohdy, A.A.R., Eaton, G.P., and Mabey, D.R., 1974, Applicaton of Surface Geophysics to
Ground-Water Investigations: Techniques in Water-Resource Investigations of the U.S.
Geological Survey, Chapter Dl, Book 2,116 p.
99.
-------
REFERENCES ON
WATER QUALITY AND GEOPHYSiCAL METHODS
Agocs, W.B., 1955, Line Spacing Effects and Determination of Optimum Spacing Illustrated by
Marmara, Ontario Magnetic Anomaly: Geophysics, v. XX, no. 4, p. 871-885.
Alger, R.P., 1966, Interpretation of Electric Logs in Fresh Water Wells in Unconsolidated
Formations, in Transactions of the Society of Professional Well Log Analysts, Seventh
Annual Logging Symposium, May 9-11, Tulsa, Oklahoma, p. CC1-CC23.
Barnes, I., and Clarke, F.E., 1964, Geochemistry of Ground Water in Mine Drainage Problems:
U.S. Geological Survey Professional Paper 473-A, p. 6.
Barrow, G.M., 1979, Physical Chemistry, (Forth Edition): McGraw-Hill, New York, New York,
Benson, R.C., Turner, M., and Vogelson, W., 1988, In Situ, Time Series Measurements for Long
Term Ground-Water Monitoring, in A.G. Collins and A.I. Johnson, editors, Ground-
Water Contamination, Field Methods, ASTM STP-963: American Society for Testing and
Materials, Philadelphia, Pennsylvania, p. 58-72.
Benson, R.C., Turner, M.S., Volgelson, W.D., and Turner, P.P., 1985, Correlation Between Field
Geophysical Measurements and Laboratory Water Sample Analysis, in Proceedings of
NWWA Conference on Surface and Borehole Geophysical Methods in Ground Water
Investigation, February 12-14,1985, Fort Worth, Texas: National Water Well
Association, Worthington, Ohio, p. 178-197.
California State Water Resources Control Board, 1988, Mine Waste Study: University of
California, Berkeley, July 1,1988, 416 p.
Carmichael, R.S., editor, 1989, Practical Handbook of Physical Properties of Rocks and Minerals:
CRC Press, Boca Raton, Florida, 741 p.
Drever, J.I., 1982, The Geochemistry of Natural Waters (Second Edition): Prentice Hall,
Englewood Cliffs, New Jersey, 437 p.
Frimpter, M.A., and Maevsky, A., 1979, Geohydrologic Impacts of Coal Development in the
Narragansett Basin, Massachusetts and Road Island: U.S. Geological Survey Waster-
Supply Paper 2062, 35 p.
Grady, S.J., and Haeni, F.P., 1984, Application of Electromagnetic Techniques in Determining
Distribution and Extent of Ground Water Contamination at a Sanitary Landfill,
Farmington, Connecticut, in D.M. Nelsen an M. Curl, editors, NWWA/EPA Conference
on Surface and Borehole Geophysical Methods in Ground Water Investigations, February
7-9,1984, San Antonio, Texas, p. 388-417.
Greenhouse, J.P., and Slaine, D.D., 1986, Geophysical Modelling and Mapping of Contaminated
Groundwater Around Three Waste Disposal Sites in Southern Ontario: Canadian
Geotechnical Journal, v, 23, p. 372-384.
100.
-------
Hem, J.D., 1989, Study and Interpretation of the Chemical Characteristics of Natural Water
(Thjrd Edition): U.S. Geological Survey Water Supply-Paper 2254, 263 p.
Hill, H.J., and Milburn, J.D., 1956, Effects of Clay and Water Salinity on Electrochemical
Behavior of Reservoir Rock, Transactions of the American Institute of Mining,
Metallurgical and Petroleum Engineers (AIME), v. 207, p. 203.
Jorgensen, D.G., 1990, Estimating Water Quality From Geophysical Logs, in F.L. Paillet and
W.R. Saunders, editors, Geophysical Applications for Geotechnical Investigations, STP
1101: American Society for Testing and Materials, Philadelphia, Pennsylvania, p 47-64.
Keller, G.V., 1966, Electrical Properties of Rocks and Minerals, in Handbook of Physical
Constants (Revised Edition): in S.P. Clark, editor, Geological Society of America Memoir
97, p. 553-557.
Keller, G.V., 1989, Electrical Properties, in R.S. Carmichael, editor, Practical Handbook of
Physical Properties of Rocks and Minerals: CRC Press, Boca Raton, Florida, p. 361-427.
Keller, G.V., and Frischknecht, F.C., 1966, Electrical Methods in Geophysical Prospecting:
Pergamon Press, New York, New York, 515 p.
Kendal, M.G., and Moran, P.A.P., 1963, Geometrical Probability, in Griffins' Statistical
Monographs and Courses, No. 10: Hafner Publishing Company, New York, New York,
125 p.
Keys, W.S., 1989, Borehole Geophysics Applied to Ground Water Investigations: National Water
Well Association, Dublin, Ohio, 313 p.
Keys, W.S., and MacCary, L.M., 1971, Application of Borehole Geophysics to Water-Resource
Investigations: U.S. Geological Survey Techniques of Water-Resource Investigations,
Book 2, Chapter El, 126 p.
Kwader, T., 1985, Resistivity-Porosity Cross Plots for Determining In-Situ Formation Water
Quality-Case Examples, i/rProceedings of NWWA Conference on Surface and Borehole
Geophysical Methods in Ground Water Investigation, February 12-14, 1985, Fort Worth,
Texas: National Water Well Association, Worthington, Ohio, p. 415-424.
Laxen, D.P.H., 1977, A Specific Conductance Method for Quality Control in Water Analysis:
Water Research, v. 11, p. 91-94.
Lind, C.J., 1970, Specific Conductance as a Means of Estimating Ionic Strength: U.S. Geological
Survey Professional Paper 700-D, p. D272-D280.
Lynch, EJ., 1962, Formation Evaluation: Harper and Row Publishers, New York, New York, 422
P-
Mayo, A.L., Nielsen, P J., Loucks, M., and Brimhall, W.H., 1992, The Use of Solute and Isotopic
Chemistry to Identify Flow Patterns and Factors Which Limit Acid Mine Drainage in the
Wasatch Range, Utah: Ground Water, v. 30, no. 2, p. 243-249.
101.
-------
Mazac, O., Kelley, W.E., and Landa, I., 1987, Surface Geoelectics for Groundwater Pollution and
Protection Studies: Journal of Hydrology, v. 93, p. 277-294.
McNeill, J.D., 1980, Electrical Conductivity of Soils and Rocks, Technical Note TN-5: Geonics
Limited, Ontario, Canada, 22 p.
Nordstrom, D.K., 1977, Hydrogeochemical And Microbiological Factors Affecting the Heavy
Metal Chemisty of an Acid Mine Drainage System: PhD. Disseration, Stanford University,
210 p.
Nordstrom, D.K., 1985, The Rate of Ferrous Iron Oxidation in a Stream Receiving Acid Mine
Effluent, in Selected Papers in the Hydrologic Sciences 1985: U.S. Geological Survey
Water-Supply Paper 2270, p. 113-119.
Onysko, S.J., 1985, Chemical Abatement of Acid Mine Drainage Formation: PhD. Disseration,
University of California, Berkeley, 314 p.
Pankow, J.F., 1991, Aquatic Chemistry Concepts: Lewis Publishers, Chelsea, Michigan, 673 p.
Parasnis, D.S., 1986, Principles of Applied Geophysics (Fourth Edition): Chapman Hall, New
York, New York, 402 p.
Rhoades, J.D., Raats, PAG, and Prather, RJ., 1976, Effects of Liquid-Phase Electrical
Conductivity, Water Content, and Surface Conductivity on Bulk Soil Electrical
Conductivity: Soil Science Society of America Journal, v. 40, p. 651-655.
Sarma, V.VJ., and Roa, V.B., 1963a, Variation of Electrical Resistivity of River Sands, Calcite
and Quartz Powers with Water Content: Geophysics, v. 27, no. 4, p. 470-479.
Sarma, V.VJ., and Roa, V.B., 1963b, Reply to Discussion of their Paper "Variation of Electrical
Resistivity of River Sands, Calcite and Quartz Powers with Water Content": Geophysics,
April 1963.
Singer, P.C., and Stumm, W., 1970, Acidic Mine Drainage: The Rate-Determining Step: Science,
v. 167, February 20,1970, p. 1121-1123.
Slaine, D.D., and Greenhouse, J.P., 1982, Case Studies of Geophysical Contaminant Mapping at
Several Waste Disposal Sites, in Proceeding of the Second National Symposium on
Aquifer Restoration and Ground-Water Monitoring, May 26-28, 1982, Fawcett Center,
Columbus, Ohio: National Water Well Association, Worthington, Ohio, p. 299-315.
Stumm, W., and Morgan, JJ., 1981, Aquatic Chemistry (Second Edition): John Wiley and Sons,
New York, New York, 780 p.
Telford, W.M., Geldart, L.P. and Sheriff, R.E., 1976, Applied Geophysics: Cambridge University
Press, New York, New York, 770 p.
Telford, W.M., Geldart, L.P. and Sheriff, R.E., 1990, -Applied Geophysics (Second Edition):
Cambridge University Press, New York, New York, 770 p.
102.
-------
Tweeton, D.R., Cumerlato, C.L., Hanson, J.C., and Kuhlman, H.L., 1991, Field Tests of
Geophysical Techniques for Predicting and Monitoring* Leach Solution Flow During In
Situ Mining: Geoexploration, v. 28, p. 251-268.
Vanysek, P. 1993, Ionic Conductivity and Diffusion at Infinite Dilution, in CRC Handbook of
Chemistry and Physics, 74th Edition, p. 5-90.
Worthington, P.E., 1975, Hydrogeophysical Equivalence of Water Salinity, Porosity, and Matrix
Conduction in Arenaceous Aquifers: Ground Water, v. 14, p. 224-232.
103.
-------
REFERENCES ON
D.C. RESISTIVITY GEOPHYSICAL METHODS
Ahmed, S., de Marsily, G., and Talbot, A., 1988, Combined Use of Hydraulic and Electrical
Properties of an Aquifer in a Geostatistical Estimation of Transmissivity: Ground Water,
v. 26, p. 78-86.
Al-Chalabi, M, 1969, Theoretical Resistivity Anomalies Across a Single Vertical Discontinuity:
Geophysical Prospecting, v. 17, p. 63.
Alfano, L, 1959, Introduction to the Interpretation of Resistivity Measurements for Complicated
Structural Conditions: Geophysical Prospecting, v. 7, p. 311-366.
Alfano, L. 1993, Geoelectrical Methods Applied to Structures of Arbitary Shapes: Journal of
Applied Geophysics, v. 29, p. 193-209.
al Hagrey, S.A., 1992, Waste Site Modeling Using a Combination of Electromagnetic Induction
and Resistivity Soundings: Environmental Technology, v. 13, p. 275-280.
al Hagrey, S.A., 1994, Electrical Study of Fracture Anisotropy at Falkenberg, Germany:
Geophysics, v. 59, p. 881-888.
Apparao, A., Gangadhara Rao, T., Sivarama Sastry, R., and Subrahmanya Sarma, V., 1992,
Depth of Detection of Buried Conductive Targets with Different Electrode Arrays in
Resistivity Prospecting: Geophysical Prospecting, v. 40, p. 749-760.
Ayers, J.F., 1989, Conjunctive Use of Geophysical and Geological Data in the Study of an
Alluvial Aquifer: Ground Water, v. 27, p. 625-632.
Bankey, V., and Anderson, W.L., 1989, Some Geophysical Programs, Databases and Maps from
the U.S. Geological Survey, 1971-1989: U.S. Geological Survey Open-File Report 89-0659,
15p.
Barber, C, Davis, G.B., Buselli, G., and Height, M., 1991, Remote Monitoring of Groundwater
Pollution Using Geoelectric Techniques in Undulating Sandy Terrain, Western Australia:
International Journal of Environment and Pollution, v. 1, no. 1/2, p. 97-112.
Bardossy, A., Bogardi, L, and Kelly, W.E., 1986, Geostatistical Analysis of Geoelectric Estimates
for Specific Capacity: Journal of Hydrology, v. 84, p. 81-95.
Barker, R.D., 1989, Depth of Investigation of Collinear Symmetrical Four-Electrode Array:
Geophysics, v. 54, p. 1031-1037.
Barker, R.D., 1990a, Improving the Quality of Resistivity Sounding Data in Landfill Studies, in
S.H. Ward, editor, Geotechnical and Environmental Geophysics, in Investigations in
Geophysics No. 5, Volume II, Environmental and Groundwater: Society of Exploration
Geophysicists,-Tulsa, Oklahoma, p. 201-217.
104.
-------
Barker, R.D., 1990b, Investigation of Ground Water Salinity by Geophysical Methods, in S.H.
Ward, editor, Geotechnical and Environmental Geophysics, in Investigations in
Geophysics No. 5, Volume II, Environmental and Groundwater: Society of Exploration
Geophysicists, Tulsa, Oklahoma, p. 245-251.
Bates, E.R., 1973, Detection of Subsurface Cavities: U.S. Army Engineering Waterways
Experiment Station, Miscellaneous Paper 5-73-40, 63 p.
Benson, A.K., 1993, Mapping Acid Mine Drainage (AMD) Using Geophysical Techniques and
Geochemical Analysis, A Case Study, Central Utah: Department of Geology, Brigham
Young University, Provo, Utah, 13 p.
Benson, R.C., Turner, M., Turner, P. and Vogelsong, W., 1988, In Situ, Time-Series
Measurements for Long-Term Ground-Water Monitoring, in A.G. Collins, and A.I.
Johnson, editors, Ground-Water Contamination, Field Methods, ASTM STP 963:
American Society for Testing and Materials, Philadelphia, Pennsylvania, p. 58-72.
Bhattacharyya, P. and Patra, H., 1968, Direct Current Geoelectrical Soundings: Elsevier Press,
Amsterdam, the Netherlands, 135 p.
Bisdorf, RJ., 1985, Electrical Techniques for Engineering Applications: Bulletin of Association of
Engineering Geologists, v. XXII, no. 4, p. 421-433.
Bisdorf, RJ., and Zohdy, A.A., 1990, IBM PC Programs for Automatic Processing and
Interpretation of Wenner Soundig Curves in QuickBasic 4.0: U.S. Geological Survey
Open-File Reports 90-0211-A and B.
Breusse, J J., 1963, Modern Geophysical Methods for Subsurface Water Exploration: Geophysics,
v. 28, p. 633-657.
Briz-Kishore, B.H., 1992, Drought Remedial Measures Through Resistivity Investigation in a
Typical Crystalline Region: Environmental Geology and Water Science, v. 20, no. 2, p.
79-83.
Bruehl, D.H., 1983, Use of Geophysical Techniques to Delineate Ground-Water Contamination,
in Proceeding of the Third National Symposium on Aquifer Restoration and Ground-
Water Monitoring, May 25-26, 1983, Fawcett Center, Columbus, Ohio: National Water
Well Association, Worthington, Ohio, p. 295-300.
Buselli, G., Barber, C, Davis, G.B., and Salama, R.B., 1990, Detection of Groundwater
Contamination Near Waste Disposal Sites with Transient Electromagnetics and Electrical
Methods, in S.H. Ward, editor, Investigations in Geophysics No. 5, Volume II,
Environmental and Groundwater: Society of Exploration Geophysicists, Tulsa, Oklahoma,
p. 27-39.
Buselli, G., Davis, G.B., Barber, C, Height, M.I., and Howard, S.H.D., 1992, The Application of
Electromagnetic and Electrical Methods to Groundwater Problems in Urban
Environments: Exploration Geophysics, v. 23, p 543-555.
105.
-------
Butler, D.K., and Llopis, J.L., 1990, Assessment of Anomalous Seepage Conditions, in S.H.
Ward, editor, Investigations in Geophysics No. 5, Volume II, Environmental and
Groundwater: Society of Exploration Geophysicists, Tulsa, Oklahoma, p. 153-173.
Carpenter, P.J., Calkin, S.F., and Kaufmann, R.S., 1991, Assessing a Fractured Landfill Cover
Using Electrical Resistivity and Seismic Refraction Techniques: Geophysics, v. 56, no, 11,
p. 1896-1904.
Carpenter, P.J., Kaufmann, R.S., and Price, B., 1990, Use of Resistivity Sounding to Determine
Landfill Structure: Ground Water, v. 28, no. 4, p. 569-575.
Cartwright, K., and McComas, M.R., 1968, Geophysical Surveys in the Vicinity of Sanitary
Landfills in Northeastern Illinois: Ground Water, v. 6, no, 5, p. 23-30.
Coggon, J.H., 1971, Electromagnetic and Electrical Modeling by the Finite Element Method:
Geophysics, v. 36, p. 132-155.
Cook, K.L., and Gray, R.L., 1961, Theoretical Horizontal Resistivity Profiles Over Hemispherical
Sinks: Geophysics, v. 26, p. 342-354.
Cook, K.L., and Van Nostrand, R.G., 1954, Interpretation of Resistivity Data Over Filled Sinks:
Geophysics, v. 19, p. 761-790.
Dave, N.K., Urn, T.P., and Siwik, R.S., 1986, Geophysical and Biohydrogeochemical Investigation
of an Inactive Sulfide Tailings Basin, Noranda, Quebec, in National Symposium on
Mining, Hydrology, Sedimentology, and Reclamation, Lexington, Kentucky, December 8-
11,1986, UKY Bulletin 142: University of Kentucky, p. 13-19.
Denaham, BJ., and Smith, D.L., 1984, Electrical Resistivity Investigation of Potential Cavities
Underlying a Proposed Ash Disposal Area: Environmental Geology and Water Science, v.
6, no. 1, p. 45-49.
Dey, H., and Morisson, H., 1979, Resistivity Modeling for Arbitrarily Shaped 3-D Structures:
Geophysics, v. 44, p 753-780.
Dobecki, T.L., and Romig, P.R., 1985, Geotechnical and Groundwater Geophysics: Geophysics, v.
50, p. 2621-2636.
Dutta, N., Bose, R.N., and Saikia, B.C., 1970, Detection of Solution Channels in Limestone by
Electrical Resistivity Methods: Geophysical Prospecting, v. 18, p. 405-414.
Ebraheem, A.M., Hamburger, M. W., Bayless, E.R., and Krothe, N.C., 1990, A Study of Acid
Mine Drainage Using Earth Resistivity Measurements: Ground Water, v. 28, no. 3, p.
361-368.
Evjen, H.M., 1938, Depth Factors and Resolving Power of Electrical Measurements: Geophysics,
v. 3, p. 78-95.
106.
-------
Filler, D.M., and Kuo, S.S., 1989, Subsurface Cavity Exploration Using Non-Distructive
Gepphysical Methods, in Proceedings on the Third National Outdoor Action Conference
on Aquifer Restoration, Ground Water Monitoring and Geophysical Methods, May 22-25,
1989, Orange County Convention Center, Orlando, Florida: National Water Well
Association, Dublin, Ohio, p. 827-840.
Flathe, H., 1955, Possibilities and Limitations in Applying Geoelectical Methods to
Hydrogeological Problems in the Coastal Areas of Northwest Germany: Geophysical
Prospecting, v. 3, p. 95-110.
Flathe, H., 1963, Five-Layer Master Curves for the Hydrogeological Interpretation of Geoelectric
Resistivity Measurements Above a Two-Story Aquifer: Geophysical Prospecting, v. 11, p.
471-503.
Flathe, H., 1967, Interpretaion of Geoelectrical Resistivity Measurements for Solving
Hydrogeological Problems, in Morley, L.W., editor, Mining and Groundwater Geophysics,
Economic Geology Report No. 26: Geological Survey of Canada, Department of Energy,
Mines and Resources, Ottawa, Canada, p. 580-597.
Flathe, H., 1974, Comment on The Automatic Fitting of a Resistivity Sounding by Geometrical
Progression of Depths": Geophysical Prospecting, v. 22, p. 176-180.
Flathe, H., 1976, The Role of a Geologic Concept in Geophysical Research Work for Solving
Hydrogeological Problems: Geoexploration, v. 14, p. 195-206.
Fox, R.C., Hohmann, G.W., Killpack, TJ., and Rijo, L., 1980, Topographic Effects in Resistivity
and Induced Polarization Surveys: Geophysics, v. 45, p. 75-93.
Frohlich, R.K., 1973, Detection of Fresh Water Aquifers in the Glacial Deposits of Northwestern
Missouri by Geoelectrical Methods: Water Resources Bulletin, v. 9, p 723-734.
Frohlich, R.K., 1974, Combined Geophysical and Drill Hole Investigations for Detecting Fresh-
Water Aquifers in Northwestern Missouri: Geophysics, v. 39, no. 3, p. 340-352.
Frohlich, R.K., and Kelly, W.E., 1985, The Relation Between Hydraulic Transmissivity and
Transverse Resistance in a Complicated Aquifer of Glacial Outwash: Journal of
Hydrology, v. 29, p. 215-229.
Ghosh, D.P., 1971, The Application of Linear Filter Theory to the Direct Interpretation of
Geoelectric Resistivity Sounding Measurements: Geophysical Prospecting, v. 19, p. 192-
217.
Grady, S.J., and Haeni, P.P., 1984, Determining Distribution and Extent of Ground Water
Contamination at a Sanitary Landfill, Farmington, Connecticut, in D.M. Nielsen and M.
Curl, editors, NWWA/EPA Conference on Surface and Borehole Geophysical Methods in
Ground Water Investigations, February 7-9,1984, San Antonio, Texas: National Water
Well Association, Worthington, Ohio, p. 368-382.
107.
-------
Greenfield, RJ., and Stoyer, C.H., 1976, Monitoring Ground Water Contamination with
Geophysical Methods: Transactions of the American Institute of Mining, Metallurgical
and Petroleum Engineers (AIME), v. 260, p. 20-23.
Greenhouse, J.P., and Harris, R.D., 1983, Migration of Contaminants in Groundwater at a
Landfill: A Case Study: Journal of Hydrology, v. 63, p. 177-197.
Griffiths, D.H., 1976, Application of Electrical Resistivity Measurements for the Determination of
Porosity and Permeability in Sandstones: Geoexploration, v. 14, p. 207-213.
Griffiths, D.H., and Barker, R.D., 1993, Two-Dimensional Resistivity Imaging and Modeling in
Areas of Complex Geology: Journal of Applied Geophysics, v. 29, p. 211-226.
Griffiths, D.H:, and King, R.F., 1981, Applied Geophysics for Geologists and Engineers (Second
Edition): Pergamon Press, New York, New York, 230 p.
Habberjam, G.M., 1972, The Effects of Anisotropy on Square Array Resistivity Measurements:
Geophysical Prospecting, v. 20, p. 249-266.
Habberjam, G.M., 1975, Apparent Resistivity, Anisotropy and Strike Measurements: Geophysical
Prospecting, v. 23, p. 211-247.
Habberjam, G.M., and Watkins, G.E., 1967, The Use of A Square Configuration in Resistivity
Prospecting: Geophysical Prospecting, v. 15, p. 221-235.
Haeni, P.P., Lane, J.W.Jr., and lieblich, DA., 1993, Use of Surface-Geophysical and Borehole-
Radar Methods to Detect Fractures in Crystalline Rocks, Mirror Lake Area, Grafton
County, New Hampshire, in S. Banks and D. Banks, editors, Hydrology of Hard Rocks,
Memoires of the XXIVth Congress, International Association of Hydrogeologists, 28th
June - 2nd July, Oslo, Norway, 11 p.
Hallenbach, F., 1953, Geo-Electrical Problems of the Hydyrology of West Germany Areas:
Geopysical Prospecting, v. 1, p. 241-249.
Hallof, P., 1992, Electrical: IP and Resistivity, Chapter 2, in R. Van Blaricom, compiler, Practical
Geophysics II for the Exploration Geologist: Northwest Mining Association, Spokane,
Washington, p. 39-138.
Hanson, J.C., Tweeton, D.R., and Friedel, MJ., 1993, A Geophysical Field Experiment for
Detecting and Monitoring Conductive Fluids: The Leading Edge, September 1993, p. 930-
937.
Henderson, RJ., 1992, Urban Geophysics-A Review: Exploration Geophysics, v. 23, 531-542.
Henriet, J.P., 1976, Direct Application of Dar Zarrouk Parameters in Ground Water Surveys:
Geophysical Prospecting, v. 24, p. 344-353.
Hohmann, G.W., 1982, Numerical Modeling for Electrical Geophysical Methods, in Proceedings
International Symposium on Applications of Geophysics in Tropical Regions: University
do Para, Belem, Brazil, p. 308-384.
108.
-------
Holcomb, H.T., and Jiracek, G.R., 1984, Three-Dimensional Terrain Corrections in Resistivity
Surveys: Geophysics, v. 49, p. 439-452. '
Huntley, D., 1986, Relations Between Permeability and Electrical Resistivity in Granular
Aquifers: Ground Water, v. 23, p. 466-474.
Interpex Limited, 1988, RESIXPLUS, D.C. Resistivity Data Interpretation Software and Users
Manual, Golden, Colorado.
Kalinski, R.J., Kelley, W.E., and Bogardi, I., 1993a, Combined Use of Geoelectrical Sounding and
Profiling to Quantify Aquifer Protection Properties: Ground Water, v. 31, no. 4, p. 538-
544.
Kalinski, R J., Kelley, W.E., Bogardi, I., and Pesti, G., 1993b, Electrical Resistivity Measurements
to Estimate Travel Times Through Unsaturated Ground Water Protective Layers: Journal
of Applied Geophysics, v. 3, p. 161-173.
Kehew, A.E., and Groenewold, G.H., 1983, Earth Resistivity Investigation in Reclaimed Surface
Lignite Mine Spoil, Report of Investigation No. 77: North Dakota Geological Survey, 92
P-
Keller, G.V., 1993, Electrical and Electromagnetic Methods in Areas of Complex Geology:
Journal of Applied Geophysics, v. 29, p. 181-192.
Keller, G.V., and Frischknecht, F.C., 1966, Electrical Methods in Geophysical Prospecting:
Pergamon Press, New York, New York, 527 p.
Kelly, W.E., 1976, Geoelectric Soundings for Delineating Ground-Water Contamination: Ground
Water v. 14, no. 1, p. 6-10.
Kelly, W.E., 1977, Geoelectric Soundings for Estimating Aquifer Hydraulic Conductivity: Ground
Water, v. 15, no. 6, p. 420-425.
Kelly, W.E., Bogardi, I. Nicklin, M., and Bardossy, A., 1988, Combining Surface Geoelectrics and
Geostatistics for Estimating the Degree and Extent of Ground-Water Pollution, in A.G.
Collins and A.I. Johnson, editors, Ground-Water Contamination, Field Methods, ASTM
STP-963: American Society for Testing and Materials, Philadelphia, Pennsylvania, p. 73-
85.
Kelly, W.E., and Mares, S., editors, 1993, Applied Geophysics in Hydrologeological and
Engineering Practice, in Developments in Water Science, No. 44: Elsevier Science
Publishers B.V., New York, New York, 289 p.
Kelly, W.E., and Reiter, P.P., 1984, Influence of Anisotropy on Relationships Between Electrical
and Hydraulic Properties of Aquifers: Journal of Hydrology, v. 74, p. 311-321.
Klefstad, G., Sendlein, L.V.A., and Palmquist, R.C., 1975, Limitation of the Electrical Resistivity
Methods in Landfill Investigations: Ground Wa'ter, v. 13, p. 418-427.
109.
-------
Koefoed, O., 1976a, Progress in the Direct Interpretation of Resistivity Soundings: An Algorithm:
Geophysical Prospecting, v. 24, p. 233-240.
Koefoed, O., 1976b, Recent Developments in the Direct Interpretation of Resistivity Soundings:
Geoexploration, v. 14, p. 243-250.
Koefoed, O., 1979, Geosoundings Principles, 1, Resistivity Soundings Measurements, in Methods
in Geochemistry and Geophysics, 14A: Elsevier Scientific Publishing Co., New York,
New York, 276 p.
Kosinski, W.K., and Kelly, W.E., 1981, Geoelectric Soundings for Predicting Aquifer Properties:
Ground Water, v. 19, no. 2, p. 163-171.
Krulc, Z., and"Mladenovic, M., 1969, Application of Geoelectrical Methods to Groundwater
Exploration of Unconsolidated Formations in Semi-Arid Areas: Geoexploration, v. 7, p.
83-95.
Kunetz, G., 1966, Principles of Direct Current Resistivity Prospecting, Geoexplorations
Monographs, Series 1, No. 1, H. Braekken and R. van Nostrand, editors: Geopublications
Associates, Berlin, Germany, 103 p.
Ladwig, KJ., 1982, Delineation of Zones of Acid Mine Drainage Using Surface Geophysics, in
D.H. Graves, editor, Proceeding 1982, Symposium on Surface Mining, Hydrology,
Sedimentology and Reclamation, UKY Bulletin 129: University Kentucky, College of
Agriculture, Lexington, Kentucky, p. 279-287.
Lane, J.W., Jr., haeni, F.P., and Watson, W.M., in press, Use of A Square-Array Direct-Current
Resistivity Method to Detect Fractures in Crystalline Bedrock in New Hampshire:
Ground Water.
Larzeg, H., 1973, Master Curves for the Wenner Array, in Scientific Series No. 15: Department
of the Environment, Ottawa, Canada, 109 p.
Lennox, D.H., and Carlson, V., 1967a, Geophysical Exploration for Buried Valleys in Alberta:
Geophysics, v. 32, p. 331-362.
Lennox, D.H., and Carlson, V., 1967b, Integration of Geophysical Methods for Groundwater
Exploration in the Prairie Provinces, Canada, in Morley, L.W., editor, Mining and
Groundwater Geophysics, Economic Geology Report No. 26: Geological Survey of
Canada, Department of Energy, Mines and Resources, Ottawa, Canada, p. 517-535.
Logn, O., 1954, Mapping Nearly Vertical Discontinuities by Earth Resistivities: Geophysics, v. 19,
p. 739-760.
Maillet, R., 1947, The Fundamental Equations of Electrical Prospecting: Geophysics, v. 12, p.
529-556.
Mallik, S.B., Bhattacharya, D.C., Nag, S.K., 1983, Behavior of Fractures in Hard Rock-A Study
by Surface Geology and Radial V.E.S. Method: Geoexploration, v. 21, p. 181-189.
110.
-------
Mark, D.L., Williams, D.S., and Huntley, D., 1986, Applications of Dipole-Dipole Resistivity
Surveys to a Hydrogeologic Investigation: in Proceedings of Surface and Borehole
Geophysical Methods and Ground Water Instrumentation: National Water Well
Association, Dublin, Ohio, p. 151-162.
Mazac, O., Cislerova, M. Kelley, W.E., Landa, I., and Venhodova, D., 1990, Determination of
Hydraulic Conductivities by Surface Geoelectric Methods, in S.H. Ward, editor,
Geotechnical and Environmental Geophysics, in Investigations in Geophysics No. 5,
Volume II, Environmental and Groundwater: Society of Exploration Geophysicists, Tulsa,
• Oklahoma, p. 125-131.
Mazac, O., Kelley, W.E., and Landa, I., 1985, A Hydrogeophysical Model for Relations Between
Electrical and Hydraulic Properties of Aquifers: Journal of Hydrology, v. 79, p. 1-19.
Mazac, O., Kelley, W.E., and Landa, L, 1987, Surface Geoelectics for Groundwater Pollution and
Protection Studies: Journal of Hydrology, v. 93, p. 277-294.
Mazac, O., Kelley, W.E., and Landa, I., 1992, Geoelectrics in Comprehensive Ground Water
Contamination Studies, in DM. Nielsen and M.N. Sara, editors, Current Practices in
Ground Water and Vadoze Zone Investigations, ASTM STP-1118: American Society for
Testing and Materials, Philadelphia, Pennsylvania, p. 79-89.
Mazac, O., and Landa, I., 1979, On Determination of Hydraulic Conductivity and Transmissivity
of Granular Aquifers by Vertical Electric Soundings: Journal of Geological Sciences, v.
16, p. 123-139.
Mbonu, P.D.C., Ebeniro, J.O., Ofoegbu, CO., and Erine, A.S., 1991, Geoelectric Sounding for
the Determination of Aquifer Characteristics in Parts of Umuahia Area of Nigeria:
Geophysics, v. 56, no. 2, p. 284-291.
Meinardus, H.A., 1970, Numerical Interpretation of Resistivity Soundings Over Horizontal Beds:
Geophysical Prospecting, v. 18, p. 415-433.
Merkel, R.H., 1972, The Use of Resistivity Techniques to Delineate Acid Mine Drainage in
Groundwater: Ground Water, V. 10, no. 5, p. 38-42.
Merkel, R.H., and Kaminski, J.T., 1972, Mapping Ground Water by Using Electrical Resistivity
with a Buried Current Source: Ground Water, v. 10, no. 2, p. 18-25.
Milsom, J., 1989, Field Geophysics-Geological Society of London Handbook: Halsted Press, John
Wiley and Sons, New York, New York, 182 p.
Mooney, H.M., 1980, Handbook of Engineering Geophysics, Volume 2, Electrical Resistivity:
Bison Instruments, Minneapolis, Minnesota, 78 p.
Mooney, H.M., Orellana, E., Pickett, H., and Turnheim, L., 1966, A Resistivity .Computation
Method for Layered Earth Models: Geophysics, v. 31, p.192-302.
Mooney, H.M., and Wetzel, W., 1954, Master Curves for a Two, Three, and Four Layer Earth:
University of Minnesota Press, Minneapolis, Minnesota, 145 p.
111.
-------
Morley, L.W., 1967, editor, Mining and Groundwater Geophysics, Economic Geology Report No.
26nGeological Survey of Canada, Proceedings of the Ganadial Centennial Conference on
Mining and Groundwater Geophysics, Niagara Falls, Canada, October 1967: Department
of Energy, Mines and Resources, Ottawa, Canada, 722 p.
Mundry, E., 1984, Geoelectric Model Calculations for 2-D Resistivity Distributions: Geophysical
Prospecting, v. 32, p. 124-131.
Muscat, M., and Evinger, H.H., 1941, Current Penetration in Direct Current Prospecting:
Geophysics, v. 6, p. 297-427
Nelson, R.G., and Haigh, J.H., 1990, Geophysical Investigations of Sinkholes n Lateritic Terrains,
in S.H.. Ward, editor, Geotechnical and Environmental Geophysics, in Investigations in
Geophysics No. 5, Volume III, Geotechnical: Society of Exploration Geophysicists, Tulsa,
Oklahoma, p. 133-153.
Niwas, S., and Singhal, D.C., 1981, Estimation of Aquifer Transmissivity From Dar Zarrouk
Parameters, in Porous Media: Journal of Hydrology, v. 50, p. 393-399.
Orellana, E., and Mooney, H.M., 1966, Master Tables and Curves for Vertical Electrical
Soundings Over Layered Structures: Madrid Interciecia, 150 p.
Orellana, E. and Mooney, H.M., 1970, Wenner Master Curves for Geoelectrical Soundings:
Madrid Intercienia, 48 p.
Omdorff, R.C., Dodd, K, Gunnells, G.B., and Sakss, Y., 1989, Computer Programs Released as
U.S. Geological Survey Publications Through August 1989: U.S. Geological Survey Open-
File Report, 89-0618, 70 p.
Owen, W.P., Park, S.K., and Lee, T., 1991, Delineation of a Discontinous Aquitard with Vertical
Electrical Soundings, San Bernardino Valley, California: Ground Water, v. 29, p. 418-424.
Page, L.M., 1968, Use of the Electrical Resistivity Method for Investigating Geologic and
Hydrologic Conditions in Santa Clara County, California: Ground Water, v. 6, no. 5, p.
31-40.
Parasnis, D.S., 1973, Mining Geophysics (2nd Edition): Elsevier, New York, New York, 395 p.
Parasnis, D.S., 1986, Principles of Applied Geophysics (Fourth Edition): Chapman Hall, New
York, New York, 402 p.
Park, S.K., Lambert, D.W., and Lee, T., 1984, Investigation by DC Resistivity Methods of a
Ground-Water Barrier Beneath the San Bernardino Valley, Southern California: Ground
Water, v. 28, p. 344-349.
Pennington, D., 1985, Selection of Proper Surface Resistivity Techniques and Equipment for
Evaluation of Groundwater Contamination, in Proceedings of NWWA Conference on
Surface and Borehole Geophysical Methods'in Ground Water Investigation, February 12-
14, 1985, Fort Worth, Texas: National Water Well Association, Worthington, Ohio, p.
23-33.
112.
-------
Ponzini, G., Ostroman, A., and Molinari, M., 1984, Empirical Relation Between Electrical
Transverse Resistance and Hydraulic Conductivity: Geoexploration, v. 22, p. 1-15.
^
Pridmore, D.F., Hohmann, G.W., Ward, S.H., and Sill, W.R., 1981, An Investigation of Finite
Element Modeling for Electrical and Electromagnetic Data in Three Dimensions:
Geophysics, v. 46, p. 1009-1024.
Ringstad, C.A., and Bugenig, D.C., 1984, Electrical Resistivity Studies to Delineate Zones of
Acceptable Ground Water Quality: Ground Water Monitoring Review, v. 4, no. 4, Fall
1984, p. 66-69.
Ritzi, R.W., Jr., and Andolsek, R.H., 1992, Relation Between Anisotropic Transmissivity and
Azimuthal Resistivity Surveys in Shallow Fractured, Carbonate Flow Systems: Ground
Water,-v. 30, no. 5, p. 774-780.
Roberts, Roger-Lee, 1989, A Multi-Technique Geophysical Approach to the Study of Landfills
and Potential Groundwater Contamination, Master's Thesis: Purdue University, 247 p.
Ross, H.P., Mackelprang, D.E., and Wright, P.M., 1990, Dipole-Dipole Electrical Resistivity
Surveys at Waste Disposal Study Sites in Northern Utah, in S.H. Ward, editor,
Geotechnical and Environmental Geophysics, in Investigations in Geophysics No. 5,
Volume II, Environmental and Groundwater: Society of Exploration Geophysicists, Tulsa,
Oklahoma, p. 145-152.
Roy, A., 1972, Depth of Investigation in Wenner, Three-Electrode and Dipole-Dipole Resistivity
Methods: Geophysical Prospecting, v. 20, p. 329-340.
Roy, A., and Apparao, A., 1971, Depth of Investigation in Direct Current Methods: Geophysics,
v. 36, no. 5, p. 943-959.
Ruby, R J., and Caoile, J.A., 1984, Utilization of Shallow Geophysical Sensing at Two Abandoned
Municipal/Industrial Waste Landfills on the Missouri River Floodplain: Ground Water
Monitoring Review, v. 4, no. 4, Fall 1984, p. 57-65.
Rumbaugh, III, J.O., Caldwell, J.A., and Shaw, ST., 1987, A Geophysical Monitoring Program
for a Sanitary Landfill, Implementation and Preliminary Analysis, in Proceeding of First
Outdoor Action Conference on Aquifer Restoration, Ground Water Monitoring and
Geophysical Methods: National Water Well Association, Dublin, Ohio, p. 487-503.
Smith, D.L., and Randazzo, A.F., 1989, Application of Electrical Resistivity Measurements in the
Identification of Preferred Zones of Groundwater Transmissivity, in Proceedings on the
Third National Outdoor Action Conference on Aquifer Restoration, Ground Water
Monitoring and Geophysical Methods, May 22-25,1989, Orange County Convention
Center, Orlando, Florida: National Water Well Association, Dublin, Ohio, p. 979-992.
Soil Test, Inc., 1968, Earth Resistivity Manual, Evanston, Illinois, 52 p.
Speigel, RJ., Sturdivant, V.R., and Owen, T.E., 1980,. Modeling Resistivity Anomalies from
Localized Voids Under Irregular Terrain: Geophysics, v. 45, p. 1164-1183.
113.
-------
Stefanescu, S., and Stefanescu, D., 1974, Mathmatical Models of Conducting Ore Bodies for
Direct Current Electrical Prospecting: Geophysical Prospecting, v. 22, p. 1246-1260.
Stierman, D.J., and Ruedisili, L.C., 1988, Integrating Geophysical and Hydrological Data: An
Efficient Approach to Remedial Investigations of Contaminated Ground Water, in A.G.
Collins ;and A. I. Johnson, editors, Ground-Water Contamination: Field Methods, ASTM
STP 963: American Society for Testing and Materials, Philadelphia, Pennsylvania, p. 43-
57.
Stewart, m., and Wood, J., 1990, Geological and Geophysical Characteristics of Fracture Zones in
a Tertiary Carbonate Aquifer, Florida, in S.H. Ward, editor, Geotechnical and
Environmental Geophysics, in Investigations in Geophysics No. 5, Volume II,
Environmental and Groundwater: Society of Exploration Geophysicists, Tulsa, Oklahoma,
p. 235-243.
Stierman, D J., 1984, Electrical Methods of Detecting Contaminated Groundwater at Stringfellow
Waste Disposal Site, Riverside County, California: Environmental Geology and Water
Science, v. 6, no. 1, p. 11-20.
Stollar, R.L., and Roux, P., 1975, Earth Resistivity Surveys-A Method for Defining Ground-water
Contamination: Ground Water, v. 13, no. 2, p. 145-150.
Taylor, R.W., and Cherkauer, D.S., 1984, The Application of Combined Seismic and Electrical
Measurements to the Determination of Hydraulic Conductivity of a Lake Bed: Ground
Water Monitoring Review, v. 4, no. 4, Fall 1984, p. 78-85.
Taylor, R.W., and Fleming, A.H., 1988, Characterizing Jointed Systems by Azimuthal Resistivity
Surveys: Ground Water, v. 26, p. 464-474.
Telford, W.M., Geldart, L.P. and Sheriff, R.E., 1976, Applied Geophysics: Cambridge University
Press, New York, New York, 770 p.
Telford, W.M., Geldart, L.P. and Sheriff, R.E., 1990, Applied Geophysics (Second Edition):
Cambridge University Press, New York, New York, 770 p.
Topfer, K, 1976, Representation and Interpretation of Resistivity Mapping Data in Groundwater
Prospecting in Zambia: Journal of Geophysics, v. 43, p. 147-158.
Tripp, A.C., Hohmann, G.W., and Swift, C.M., Jr., 1984, Two-Dimensional Resitivity Inversion:
Geophysics, v. 49,1708-1717.
Underwood, J.E., Laudon KJ., and Laudon, T.S., 1984, Seismic and Resistivity Investigations
Near Norway, Michigan: Ground Water Monitoring Review, v. 4, no. 4, Fall 1984, p. 86-
91.
Unz, M., 1963, Relative Resolving Power of Four Point Resistivity Configurations: Geophysics, v.
. 28, p. 447-456.
. Urish, D.W., 1981, Electrical Resistivity Hydraulic Conductivity Relationships in Glacial Outwash
Aquifers: Water Resources Research, v. 17, p. 1401-1408.
114.
-------
Urish, D.W., 1983, The Practical Application of Surface Electrical Resistivity to Detection of
Grpund-Water Pollution: Ground Water, v. 21, p. 144->152.
U.S. Environmental Protection Agency, 1978, Electrical Resistivity Evaluations at Solid Waste
Disposal Facilities, Office of Solid Waste, Report #WA-6-99-2794-A (G.O.P. Stock #0-
' 284-197), 94 p. .
van Darn, J.C., 1965, A Simple Method for the Calculation of Standard Graphs to be Used in
Gee-Electrical Prospecting: Geophysical Prospecting, v. 13, p. 37-65.
van Dam, J.C, 1976, Possibilities and Limitations of the Resistivity Method of Geoelectrical
Prospecting in the Solution of Geohydrological Problems: Geoexploration, v. 14, p. 179-
193. .
van Dam, I.C., Meulenkamp, JJ., 1967, Some Results of the Geo-electical Resistivity Method in
Ground Water Investigation in the Netherlands: Geophysical Prospecting, v. XV, no. 1, p.
92-115.
van Nostrand, R.G., 1953, Limitations on Resistivity Methods as Inferred from the Buried Sphere
Problem: Geophysics, v. 36, p. 943-959.
van Nostrand, R.G., and Cook, K.L., 1966, Interpretation of Resistivity Data: U.S. Geologic
Survey Professional Paper 499, p. 310.
van Overmeeren, R.A., 1981, A Combination of Electrical Resistivity, Seismic Refraction and
Gravity Measurements for Groundwater Exploration in Sudan: Geophysics, v. 46, p. 1304-
1313.
Verma, R.K., and Bhuin, N.C., 1979, Use of Electrical Resistivity Methods for Study of Coal
Seams in Parts of Jharia Coalfield, India: Geoexploration, v. 17, p. 163-176.
Vozoff, K., 1958, Numerical Resistivity Analysis: Horizontal Layers: Geophysics, v. 23, p. 536-
556.
Ward, S.H., 1990, Resistivity and Induced Polarizaton Methods, in S.H. Ward, editor,
Geotechnical and Environmental Geophysics, in Investigations in Geophysics No. 5,
Volume I, Review and Tutorial: Society of Exploration Geophysicists, Tulsa, Oklahoma,
p. 147-189.
Warner, D.L., 1969, Preliminary Field Studies Using Earth Resistivity Measurements for
Delineating Zones of Contaminated Ground Water: Ground Water, v. 7, no. 1, p. 6-16.
White, P.A., 1994, Electrode Arrays for Measuring Ground Water Flow Direction and Velocity:
Geophysics, v. 59, p. 192-201.
Wilt, M.J., and Tsang., C.F., 1985, Monitoring of Subsurface Contaminants with Borehole/Surface
Resistivity Measurements, in Proceedings of NWWA Conference on Surface and
Borehole Geophysical Methods in Ground Water Investigation, February 12-14, 1985,
Fort Worth, Texas: National Water Well Association, Worthington, Ohio, p. 167-177.
115.
-------
Worthington, P.P., 1975, Quantitative Geophysical Investigations of Granular Aquifers:
Gepphysical Surveys, v. 2, p. 3. *
Worthington, P.P., 1976, Hydrogeophysical Equivalence of Water Salinity, Porosity and Matrix
Conduction in Arenaceous Aquifers: Ground Water, v. 14, p. 224-232.
Worthington, P.P., 1977, Geophysical Investigations of Ground Water,Resources in the Kalahari
Basin: Geophysics, v. 42, no. 4, p. 838-849.
Worthington, P., and Griffiths, D., 1976, Application of Geophysical Methods in Exploration and
Development of Sandstone Aquifers: Quarterly Journal of Engineering Geology, v. 8, p.
73.
Zohdy, A.A.R, 1965, The Auxiliary Point Method of Electrical Sounding Interpretation, and Its
Relationship to the Dar Zarrouk Parameters: Geophysics, v. 30, p. 644-660.
Zohdy, A.A.R., 1968a, A rapid Graphical Method for Interpretation of A- and H-type Electrical
Soundings: Geophysics, v. 33, p. 822-833.
Zohdy, A.A.R., 1968b, The Effect of Current Leakage and Electrode Spacing Errors on
Resistivity Measurements: U.S. Geological Survey Professional Paper 600-D, p. D258-
D264.
Zohdy, AA.R., 1969a, The Use of Schlumberger and Equatorial Soundings in Ground Water
Investigations Near El Paso, Texas: Geophysics, v. 34, p. 713-728.
Zohdy, A.A.R., 1969b, A New Method for Differential Resistivity Soundings: Geophysics, v. 34,
p. 924-943. .
Zohdy, A.A.R., 1970a, Variable Azimuth Schlumberger Soundings and Profiling Near a Vertical
Contact: U.S. Geological Survey Bulletin 1313-A, 22 p.
Zohdy, A.A.R., 1970b, Geometric Factors of Bipole-Dipole Arrays: U.S. Geological Survey
Bulletin 1313-B, 26 p.
Zohdy, A.A.R., 1974, Use of Dar Zarrouk Curves in the Interpretation of Vertical Electrical
Sounding Data: U.S. Geological Survey Bulletin 1313-D, 41 p.
Zohdy, A.A.R., 1975, Automatic Interpretation of Schlumberger Sounding Curves Using modified
Dar Zarrouk Functions: U.S. Geological Survey Bulletin 313-E..
Zohdy, A.A.R., and Bisdorf, RJ., 1989, Programs for the Automatic Processing and
Interpretation of Schlumberger Sounding Curves in Quick Basic: U.S. Geological Survey
Open-File Report 89-137-A and B, 64 p.
Zohdy, A.A.R., Eaton, G.P., and Mabey, D.R., 1974, Application of Surface Geophysics to
Ground-Water Investigations: Techniques of Water-Resource Investigations of the U.S.
Geological Survey, Book 2, Chapter Dl, 116 p.
116.
-------
Zohdy, A.A.R., and Jackson, D.B., 1973, Recognition of Natural Brine by Electrical Soundings
Near Salt Fork of the Brezo River, Kent and Stonewall Counties, Texas: U.S. Geological
Survey Professional Paper, 809-A, 14 p.
117.
-------
REFERENCES ON
MISE-A-LA-MASSE GEOPHYSICAL METHODS
al Hagrey, S.A., 1994, Electrical Study of Fracture Anisotropy at Falkenberg, Germany:
Geophysics, v. 59, p. 881-8
Beasley, C.W., and Ward, S.H., 1986, Three-Dimensional Mise-a-la-Misse Modeling Applied to
Mapping Fracture Zones: Geophysics, v. 51, p. 98-113.
Bhattacharya, B.B., Biswas, O., and Ghosh, H., 1984, Geoelectric Exploration for Graphite in the
Balangir District, Orissa, India: Geoexploration, v. 22, p. 129-143.
Cahyna, F. 1990, Monitoring of Artifical Infiltration Using Geoelectrical Methods, in S.H. Ward,
editor, Geotechnical and Environmental Geophysics, in Investigations in Geophysics No.
5, Volume II, Environmental and Groundwater: Society of Exploration Geophysicists,
Tulsa, Oklahoma, p. 101-106.
Clasen, M J., 1988, Application of Alternative Surface Geophysical Techniques to Hydrogeologic
Surveys, Masters Thesis: University of South Florida, Tampa, Florida, 104 p.
Eloranta, E., 1984, A Method for Calculating Mise-a-la-Masse Anomalies in the Case of High
Conductivity Contrasts by the Intergral Equation Technique: Geoexploration, v. 22, p. 77-
88
\j\J*
Jamtlid, A., Magnusson, K., Olsson, O., and Stenbreg, L., 1984, Electrical Borehole
Measurements for the Mapping of Fracture Zones in Crystalline Rock: Geoexploration, v.
22, p. 203-216.
Kelly, W.E., and Mares, S., editors, 1993, Applied Geophysics in Hydrologeological and
Engineering Practice, in Developments in Water Science, No. 44: Elsevier Science
Publishers B.V., New York, New York, 289 p.
Mazac, O., Kelley, W.E., and Landa, I., 1987, Surface Geoelectics for Groundwater Pollution and
Protection Studies: Journal of Hydrology, v. 93, p. 277-294.
Mazac, O., Kelley, W.E., and Landa, I., 1992, Geoelectrics in Comprehensive Ground Water
Contamination Studies, in D.M. Nielsen and M.N. Sara, editors, Current Practices in
Ground Water and Vadoze Zone Investigations, ASTM STP-1118: American Society for
Testing and Materials, Philadelphia, Pennsylvania, p. 79-89.
Mazac, O., Landa, L, and Kolinger, A., 1980, The Feasibility of a Hydrogeological Variant of
Mise-a-la-Masse Method: An Analysis: Journal of Geological Sciences, v. 14, p. 147-177.
Parasnis, D.S., 1973, Mining Geophysics (2nd Edition): Elsevier, New York, New York, 395 p.
Telford, W.M., Geldart, L.P. and Sheriff, R.E., 1990, Applied Geophysics (Second Edition):
Cambridge University Press, New York, New York, 770 p.
118.
-------
REFERENCES ON
INDUCED POLARIZATION GEOPHYSICAL METHODS
Anderson, W.L., and Smith, B.D., 1986, NonLinear Least-Squares Inversion of Frequency-
Domairi Induced Polarization Data-(NLSIP): U.S. Geological Survey Open-File Report
86-0280, 33p.
Barker, R.D., 1990, Investigation of Groundwater Salinity by Geophysical Methods, in S.H. Ward,
editor, Geotechnical and Environmental Geophysics, in Investigations in Geophysics No.
5, Volume II, Environmental and Groundwater: Society of Exploration Geophysicists,
Tulsa, Oklahoma, p. 201-211.
Bodmer, R., Morrison, H.F., and Ward, S.H., 1968, On Induced Polarization and Groundwater:
Geophysics, v. 33, p. 805-821.
\
Bohn, H.L., McNeal, B.C., and O'Connor, G.A., 1985, Soil Chemistry (Second Edition): John
Wiley and Sons, New York, New York, 341 p.
Breusse, JJ., 1963, Modern Geophysical Methods for Subsurface Water Exploration: Geophysics,
v. 28, p. 633-657.
Coggon, J.H., 1973, A Comparison of IP Electrode Arrays: Geophysics, v. 38, p. 737-761.
Cahyna, F. 1990, Monitoring of Artifical Infiltration Using Geoelectrical Methods, in S.H. Ward,
editor, Geotechnical and Environmental Geophysics, in Investigations in Geophysics No.
5, Volume II, Environmental and Groundwater: Society of Exploration Geophysicists,
Tulsa, Oklahoma, p. 101-106.
Cahyna, F., Mazac, O., and Venhodova, D., 1990, Detrmination of the Extent of Cyanide
Contamination by Surface Geoelectric Methods, in S.H. Ward, editor, Geotechnical and
Environmental Geophysics, in Investigations in Geophysics No. 5, Volume II,
Environmental and Groundwater: Society of Exploration Geophysicists, Tulsa, Oklahoma,,
p. 97-99.
Dieter, K., Paterson, N.R., and Grant, F.S., 1969, IP and Resistivity Type Curves for Three-
Dimensional Bodies: Geophysics, v. 34, p. 615-632.
Draskovits, P., Robot, J., and Vero, L., 1990, Application of Induced Polarization Method in
Exploration for Quaternary Sandy-Shaly Water-Bearing Formations, in J.B. Fink and E.O.
McAllister, editors, Advances in Applications and Case Histories of Induced Polarization,
Society of Exploration Geophysicists Special Publication: Society of Exploration
Geophysicists, Tulsa, Oklahoma.
Frische, R.H., and Von Buttlar, H., 1957, A Theoretical Study of Induced Electrical Polarization:
Geophysics, v. 22, p. 688-706.
Fox, R.C., Hohmann, G.W., Killpack, TJ., and Rijo, L., 1980, Topographic Effects in Resistivity
and Induced Polarization Surveys: Geophysics, v. 45, p. 75-93.
119.
-------
Griffiths, D.H., Barker, R.D., and Finch, J.W., 1981, Recent Applications of the Electrical
Resistivity and Induced Polarization Methods to Hydrogeological Problems, in A Survey
of British Hydrogeolpgy 1980: Royal Society of London, p. 85-86.
Hohmann, G.W., 1975, Three-Dimensional Induced Polarization and Electromagnetic Modeling:
Geophysics, v. 40, p. 309-324.
Hohmann, G.W., 1988, Numerical Modeling for Electromagnetic Methods, in M.N. Nabighian,
editor, Electromagnetic Methods in Applied Geophysics, in Investigations in Exploration
Geophysics, Volume I, Theory: Society of Exploration Geophysicists, Tulsa, Oklahoma.
Interpex Limited, 1988, RESIX-IP, Induced Polarization Interpretation Software and Users'
Manual, Golden, Colorado.
Kelly, W.E., and Mares, S., editors, 1993, Applied Geophysics in Hydrologeological and
Engineering Practice, in Developments in Water Science, No. 44: Elsevier Science
Publishers B.V., New York, New York, 289 p.
Marshall, D J., and Madden, T.R., 1959, Induced Polarization-A Study of Its 'Causes: Geophysics,
v. 24, p. 790-816.
Mazac, O., Cislerova, M. Kelley, W.E., Landa, I., and Venhodova, D., 1990, Determination of
Hydraulic Conductivities by Surface Geoelectric Methods, in S.H. Ward, editor,
Geotechnical and Environmental Geophysics, in Investigations in Geophysics No. 5,
Volume II, Environmental and Groundwater: Society of Exploration Geophysicists, Tulsa,
Oklahoma, p. 125-131.
Ogilvi, A.A., 1967, Geophysical Prospecting for Ground Water in the Soviet Union, in L.W.
Morley, editor, Mining and Groundwater Geophysics, Economic Geology Report No. 26,
Geological Survey of Canada: Department of Energy, Mines and Resources, Ottawa,
Canada, p. 536-543.
Ogilvi, A.A., and Kuzmina, E.N., 1972, Hydrogeologic and Engineering Geologic Possibilities for
Emphasizing the Method of Induced Potentials: Geophysics, v. 37, p. 839.
Sadek, H.S., 1983, Basic Program IPFLTR for Induced Polarization Data Reduction and
Filtering: U.S. Geological Survey Open-File Report 83-0485.
Sandberg, S.K., 1993, Examples of Resolution Improvement in Geoelectrical Soundings Applied
to Groundwater Investigations: Geophysical Prospecting, v. 41, p. 207-227.
Seigel, H.O., 1959, Mathmatical Formulation and Type Curves for Induced Polarization:
Geophysics, v. 24, p. 547-563.
Sumner, J.S., 1976, Principles of Induced Polarization for Geophysical Exploration: Elsevier
Scientific Publishing, New York, New York, 277 p.
Vacquier, v., Holmes, C.R., Kintzinger, P.R., and Lavergne, M., 1957, Prospecting for
Groundwater by Induced Electrical Polarization: Geophysics, v. 22, p. 660-687.
120.
-------
Ward, S.H., 1990, Resistivity and Induced Polorizaton Methods, in S.H. Ward, editor,
Geptechnical and Environmental Geophysics, in Investigations in Geophysics No. 5,
Volume I, Review and Tutorial: Society of Exploration Geophysicists, Tulsa, Oklahoma,
p. 147-189.
121.
-------
REFERENCES ON
ELECTROMAGNETIC GEOPHYSICAL METHODS
t
al Hagrey, S.A., 1992, Waste Site Modeling Using a Combination of Electromagnetic Induction
and Resistivity Soundings: Environmental Technology, v. 13, p. 275-280.
Barber, C, Davis, G.B., Buselli, G., and Height, M., 1991, Remote Monitoring of Groundwater
Pollution Using Geoelectric Techniques in Undulating Sandy Terrain, Western Australia:
International Journal of Environment and Pollution, v. 1/2, p. 97-112.
Barker, R.D., 1990, Investigation of Ground Water Salinity by Geophysical Methods, in S.H.
Ward, editor, Geotechnical and Environmental Geophysics, in Investigations in
Geophysics No. 5, Volume II, Environmental and Groundwater: Society of Exploration
Geophysicists, Tulsa, Oklahoma, p. 245-251.
Barlow, P.M., Ryan, B J., 1985, An Electromagnetic Method for Delineating Ground-Water
Contamination, Wood River Junction, Rhode Island: U.S. Geological Water-Supply Paper
2270, p. 35-49.
Bartel, L.C., 1990, Results From a Controlled-Source Audio Frequency Magnetotelluric Survey to
Characterize an Aquifer, in S.H. Ward, editor, Geotechnical and Environmental
Geophysics, in Investigations in Geophysics No. 5, Volume II, Environmental and
Groundwater: Society of Exploration Geophysicists, Tulsa, Oklahoma, p. 219-233.
Brooks, G.A., Olyphant, G.A., Harper, D., 1991, Applicaton of Electromagnetic Techniques in
Survey of Contaminated Groundwater at an Abandoned Mine Complex in Southwestern
Indiana, U.S.A.: Environmental Geology and Water Sciences, v. 18, no. 1, p. 39-47.
Buselli, G., Barber, C, and Davis, G.B., 1990, Detection of Groundwater Contamination Near
Waste Disposal Site with Transient Electromagnetics and Electrical Methods, in S.H.
Ward, editor, Geotechnical and Environmental Geophysics, in Investigations in
Geophysics No. 5, Volume II, Environmental and Groundwater: Society of Exploration
Geophysicists, Tulsa, Oklahoma, p. 27-39.
Buselli, G., Davis, G.B., Barber, C, Height, M.I., and Howard, S.H.D., 1992, The Application of
Electromagnetic and Electrical Methods to Groundwater Problems in Urban
Environments: Exploration Geophysics, v. 23, p 543-555.
Butler, D.K., and Llopis, J.L., 1990, Assessment of Anomalous Seepage Conditions, in S.H.
Ward, editor, Geotechnical and Environmental Geophysics, in Investigations in
Geophysics No. 5, Volume II, Environmental and Groundwater: Society of Exploration
Geophysicists, Tulsa, Oklahoma, p. 153-173.
Emilsson, G.R., and Wroblewski, R.T., 1988, Resolving Conductive Contamiant Plumes in the
Presence of Irregular Topograph, in Proceedings of the Second National Outdoor Action
Conference on Aquifer Restoration, Ground Water Monitoring and Geophysical
Methods, Volume II, May 23-26,1988, Las Vegas, Nevada: Association of Ground Water
Scientists, Worthington, Ohio, p. 617-635.
122.
-------
Geonics Limited, 1985, EM34-3 Operating Manual, Mississanga, Ontario, Canada.
Geonics Limited, 1988, Workshop on Ground Conductivity Meters, Sacramento, California.
Geonics Limited, 1991, EM31 Operating Manual, Mississanga, Ontario, Canada, 62 p.
Geonics Limited, 1992a, Bibliography, Version 2.0, February 1992, Mississanga, Ontario, Canada,
36 p.
Geonics, Ltd., 1992b, Groundwater Contamination Mapping Applications, March 1992,
Mississanga, Ontario, Canada,
36 p.
Goldstein, N.E., Benson, S.M., and Alumbaugh, D., 1990, Saline Groundwater Plume Mapping
with Electromagnetics, in S.H. Ward, editor, Geotechnical and Environmental Geophysics,
in Investigations in Geophysics No. 5, Volume II, Environmental and Groundwater:
Society of Exploration Geophysicists, Tulsa, Oklahoma, p. 17-25.
Grantham, D.G., Ellefsen, K., Haeni, P.P., 1987, Forward-Modeling Computer Program for the
Inductive Electromagnetic Ground-Conductivity Method: U.S. Geologic Survey Open-
File Report 87-0213A and B, 43 p.
Grantham, D.G., and Haeni, F.P., 1986, Forward Modeling Computer Program for the Very Low
Frequency Radio-Wave Earth-Resistivity Electromagnetic Method: U.S. Geologic Survey
Open-File Report 86-0407.
Greenfield, RJ., and Stoyer, C.H., 1976, Monitoring Ground Water Contamination with
Geophysical .Methods: Transactions of the American Institute of Mining, Metallurgical
and Petroleum Engineers (AIME), v. 260, p. 20-23.
Greenhouse, J.P., and Harris, R.D., 1983, Migration of Contaminants in Groundwater at a
Landfill: A Case Study: Journal of Hydrology, v. 63, p. 177-197.
Greenhouse, J.P., and Slaine, D.D., 1986, Geophysical Modelling and Mapping of Contaminated
Groundwater Around Three Waste Disposal Sites in Southern Ontario: Canadian
Geotechnical Journal, v, 23, p. 372-384.
Hoekstra, P., Lahti, R., Hild, J., Bates, R., and Phillips, D., 1992, Case Histories of Shallow Time
Domain Electromagnetics in Environmental Site Assessment: Ground Water Monitoring
Review, Fall 1992, p. 110-117.
Interprex Limited, 1992, EMDC 34, Electromagnetic Interpretation Software and Users' Manual,
Golden, Colorado.
Interprex Limited, 1992, EMIX 34PLUS, Electromagnetic Interpretation Software and Users'
Manual, Golden, Colorado.
Jansen, J., Haddad, B., Fassbender, W., and Jurcek, P., 1992, Frequency Domain Electromagnetic
Induction Sounding Surveys for Landfill Site Characterization Studies: Ground Water
Monitoring Review, Fall 1992, p. 103-109.
123.
-------
Keller, G.V., 1993, Electrical and Electromagnetic Methods in Areas of Complex Geology:
Journal of Applied Geophysics, v. 29, p. 181-192.
King, A., Pesowski, M., 1991, Envirnomental Application of Surface Geophysics, Presented at
93rd Annual General Meeeting of CIM: Canadian Institue of Mining,Metallurgy and
Petroleum, Vancouver, Canada.
King, A., Pesowski, M., 1993, Environmental Applications of Surface and Airborne Geophysics in
Mining: CIM Bulletin, Canadian Institute of Mining, Metallurgy and Petroleum, v: 86, no.
966, p. 58-67.
King, A., and Sartorelli, A.N., 1991, Mapping Acidified Groundwater Using Surface Geophysical
Methods: International Conference on the Abatement of Acidic Drainage, Montreal,
Quebec, p 451-487.
Lahti, R.M., and Hoekstra, P., 1991, Geophysical Surveys for Mapping Migration of Brines from
Evaporation Pits and Ponds, in Proceedings of the Symposium on the Application of
Geophysics to Engineering and Environmental Problems, March 11-14, 1991, University
of Tennessee Knoxville, Tennessee: Society of Engineering and Mineral Exploration
Geophysicists, p. 65-71.
Ladwig, KJ., 1982, Electomagnetic Induction Methods for Monitoring Acid Mine Drainage:
Ground Water Monitoring Review, Winter 1982, p. 46-51.
Lasky, L.R., 1985, EM Conductivity for Leachage Plume Definition: A Case Study, in Abstracts
of Association of Engineering Geologists, 28th Annual Meeting, October 7-11, 1985
Winston-Salem, North Carolina, p. 68.
Lawrence, T.A., and Boutwell, G.P., 1990, Predicting Stratigraphy at Landfill Sites Using
Electromagnetics, in A. Landva and G.D. Knowles, editors, Geotechnics of Waste Fills-
Theory and Practice, ASTM STP 1070: American Society for Testing and Materials,
Philadelphia, Pennsylvania, p. 30-40.
Lyverse, M.A., 1989, Surface Geophysical Techniques and Test Drilling Used to Assess Ground-
Water Contamination by Chlorides in an Alluvial Aquifer, in Proceedings on the Third
National Outdoor Action Conference on Aquifer Restoration, Ground Water Monitoring
and Geophysical Methods, May 22-25,1989, Orange County Convention Center, Orlando,
Florida: National Water Well Association, Dublin, Ohio, p. 993-1006.
McNeill, J.D., 1980, Electromagnetic Terrain Conductivity Measurements at Low Induction
Numbers, Technical Note TN-6: Geonics Limited, Mississauga, Ontario, Canada, 15 p.
McNeill, J.D., 1983, EM34-3 Survey Interpretation Techniques, Technical Note TN-8: Geonics
Limited, Mississauga, Ontario, Canada, 7 p.
McNeill, J.D., 1985, EM34-3 Measurements at Two Inter-Coil Spacings to Reduce Sensitivity to
Near-Surface Material, Technical Note TN-19: Geonics Limited, Mississauga, Ontario,
Canada, 3 p.
124.
-------
McNeill, J.D., 1990, Use of Electromagnetic Methods for Groundwater Studies, in S.H. Ward,
editor, Geotechnical and Environmental Geophysics, in Investigations in Geophysics No.
5, Volume I, Review and Tutorial: Society of Exploration Geophysicists, Tulsa,
Oklahoma, p. 191-218.
McNeill, J.D., and Labson, V., 1990, Geologic Mapping using VLF Radio Waves, in M. N.
Nabighian, editor, Electromagnetic Methods in Applied Geophysics, Volume 2: Society of
Exploration Geophysicists.
Mazac, O., Cislerova, M. Kelley, W.E., Landa, L, and Venhodova, D., 1990, Determination of
Hydraulic Conductivities by Surface Geoelectric Methods, in S.H. Ward, editor,
Geotechnical and Environmental Geophysics, in Investigations in Geophysics No. 5,
Volume II, Environmental and Groundwater: Society of Exploration Geophysicists, Tulsa,
Oklahoma, p. 125-131.
Monier-Williams, M.E., Greenhouse, J.P., Mendes, J.M., and Ellert, N., 1990, Terrain
Conductivity Mapping with Topographic Corrections at Three Waste Disposal Sites in
Brazil, in S.H. Ward, editor, Geotechnical and Environmental Geophysics, in
Investigations in Geophysics No. 5, Volume II, Environmental and Groundwater: Society
of Exploration Geophysicists, Tulsa, Oklahoma, p. 41-55.
Morgenstem, KA., and Syverson, T.L., 1988, Determination of Contaminant Migration in
Vertical Faults and Basalt Rows with Electromagnetic Conductivity Techniques, in
Proceedings of the Second National Outdoor Action Conference on Aquifer Restoration,
Ground Water Monitoring and Geophysical Methods, Volume II, May 23-26, 1988, Las
Vegas, Nevada: Association of Ground Water Scientists, Worthington, Ohio, p. 597-616.
Parasnis, D.S., 1973, Mining Geophysics (2nd Edition): Elsevier, New York, New York, 395 p.
Parasnis, D.S., 1986, Principles of Applied Geophysics (Fourth Edition): Chapman Hall, New
York, New York, 402 p.
Ruby, RJ., and Caoile, JA., 1984, Utilization of Shallow Geophysical Sensing at Two Abandoned
Municipal/Industrial Waste Landfills on the Missouri River Floodplain: Ground Water
Monitoring Review, v. 4, no. 4, Fall 1984, p. 57-65.
Sartorelli, A.N., Pesowski, M.S., Wesselingh, L.G., 1990, Magnetic Induction Measurements in
Support of Environmental Studies-Western Canada Examples: in Proceedings of 52nd
EAEG Meeting and Technical Exhibition, May 28-June 1, 1990, Copenhagen.
Sanders, W.R., and Cox, S.A., 1988, Technical and Logistical Problems Associated with the
Implementation and Integration of Surface Geophysical Methods in Inactive Hazardous
Waste Site Investigations, in Proceedings of the Second National Outdoor Action
Conference on Aquifer Restoration, Ground Water Monitoring and Geophysical
Methods, Volume II, May 23-26, 1988, Las Vegas, Nevada: Association of Ground Water
Scientists, Worthington, Ohio, p. 637-653.
125.
-------
Sharma, P.V., 1986, Geophysical Methods in Geology (Second Edition): Elsevier Science
Publishing Co., New York, New York, 442 p.
\
Slaine, D.D., and Greenhouse, J.P., 1982, Case Studies of Geophysical Contaminant Mapping at
Several Waste Disposal Sites, in Proceedings of the Second National Symposium on
Aquifer Restoration and Ground-Water Monitoring, May 26-28, 1982, Fawcett Center,
Columbus, Ohio: National Water Well Association, Worthington, Ohio, p. 299-315.
Stewart, M. 1990, Rapid Reconnaissance Mapping of Fresh-Water Lenses on Small Oceanic
Islands, in S.H. Ward, editor, Geotechnical and Environmental Geophysics, in
Investigations in Geophysics No. 5, Volume II, Environmental and Groundwater: Society
of Exploration Geophysicists, Tulsa, Oklahoma, p. 57-66.
Stewart, M., and Bretnall, R., 1986, Interpretation of VLF Resistivity Data for Ground Water
Contamination Surveys: Ground Water Monitoring Review, Winter 1986, p. 71-75.
Street, G J., and Engel, R., 1990, Geophysical Surveys of Dryland Salinity, in S.H. Ward, editor,
Geotechnical and Environmental Geophysics, in Investigations in Geophysics No. 5,
Volume II, Environmental and Groundwater: Society of Exploration Geophysicists, Tulsa,
Oklahoma, p. 187-199.
Syed, T., Zonge, K.L., Figgins, S., and Anzzolin, A.R., 1985, Application of Controlled Source
Audio Magnetotellurics (CSAMT) Survey to Delineate Zones of Ground Water
Contamination-A Case History, in Proceedings of NWWA Conference on Surface and
Borehole Geophysical Methods in Ground Water Investigation, February 12-14,1985,
Fort Worth, Texas: National Water Well Association, Worthington, Ohio, p. 282-311.
Watzlaf, G.R., and Ladwig, KJ., 1987, Electromagnetic Conductivity Surveys to Indentify Acid
Sources and Flow Patterns U.S. Coal Mines, in Proceedings, Acid Mine Drainage
Seminar/Workshop Halifax, Nova Scotia, March 1987, p. 187-213.
Weber, D.D., Scholl, J.F., LaBrecque, D J., Walther, E.G., and Evans, R.B., 1984, Spactial
Mapping of Conductive Ground Water Contamination with Electromagnetic Induction:
Ground Water Monitoring Review, v. 4, no. 4, Fall 1984, p. 70-77.
Wightman, W.E., Martinek, B.C., and Hammermeister, D., 1992, Geophysical Methods Used to
Guide Hydrogeologic Investigations at an UMTRA Site Near Grand Junction, Colorado,
in D.M. Nielsen and M.N. Sara, editors, Current Practices in Ground Water And Vadoze
Zone Investigations, STP-1118: American Society for Testing and Materials, Philadelphia,
Pennsylvania, p. 69-78.
126.
-------
REFERENCES ON
SELF POTENTIAL GEOPHYSICAL METHODS
Becker, A., and Telford, W.M., 1965, Spontanteous Polarization Studies: Geophysical
Prospecting, v. 13, p. 173-188.
Bisdorf, R J., 1985, Electrical Techniques for Engineering Applications: Bulletin of Association of
Engineering Geologists, v. XXII, no. 4, p. 421-433.
Bogoslovsky, V.A., Kuzmina, E.N., Ogilvy, A.A., and Strakhova, N.A., 1979, Geophysical
Methods for Controlling The Seepage Regime in Earth Dams: Bulletin International
Association of Engineering Geology, v. 20, p. 249-251.
Bogoslovsky, V.A., and Ogilvy A.A., 1970, Natural Potential Anomalies as a Quantitative Index
of the Rate of Water Seepage from Reservoirs: Geophysical Prospecting, v. 18, p. 261-
268.
Bogoslovsky, V.A., and Ogilvy A.A., 1972, The Study of Streaming Potentials on Fissured Media
Models: Geophysical Prospecting, v. 20, p. 109-117.
Bogoslovsky, V.A., and Ogilvy. A.A., 1973, Deformations of Natural Electric Fields Near
Drainage Structures: Geophysical Prospecting, v. 321, no. 4, p. 716-723.
Bogoslovsky, VA., and Ogilvy A.A., 1977, Geophysical Methods for Investigation of Landslides:
Geophysics, v. 42, no. 3, p. 562-571.
Butler, D.K., and Llopis, J.L., 1990, Assessment of Anomalous Seepage Conditions, in S.H.
Ward, editor, Geotechnical and Environmental Geophysics, in Investigations in
Geophysics No. 5, Volume II, Environmental and Groundwater: Society of Exploration
Geophysicists, Tulsa, Oklahoma, p. 153-173.
Cony, D.E., 1985, Spontaneous Polarization Associated with Porphyry Sulphide Mineralization:
Geophysics, v. 50, p. 1020-1034.
Corwin, R.F., 1990, The Self-Potential Method for Environmental And Engineering Applications,
in S.H. Ward, editor, Geotechnical and Environmental Geophysics, in Investigations in
Geophysics No. 5, Volume I, Review and Tutorial: Society of Exploration Geophysicists,
Tulsa, Oklahoma, p. 127-145.
Corwin, R.F., and Hoover, D.B., The Self-Potential Method in Geothermal Exploration:
Geophysics, v. 44, no. 2, p. 226-245.
Erchul, R.A., 1988, The Use of Self Potential in the Detection of Subsurface Flow Patterns In
and Around Sinkholes, in Geotechnical Application of the Self Potential Method (SP),
Report 1, U.S. Army Corp of Engineers, Technical Report REMR-GT-6, 23 p.
Ernstson, K., and Scherer, H.U., 1986, Selp Potential Variation with Time and Their Relation to
Hydrogeologic and Meteorological Parameters: Geophysics, v. 51, p. 1967-1977.
127.
-------
Fitterman, D.V., 1976, Calculations of Self-Potential Anomalies Generated by Eh Potential
Gradients: U.S. Geological Survey Open-File Report 76-94, 32 p.
Fitterman, D.V., 1979, Calculations of Self-Potential Anomalies Near Vertical Contacts:
Geophysics, v. 44, no,. 2, p. 195-205.
Fitterman, D.V., 1978, Electrokinetic and Magnetic Anomalies Associated with Dilatant Regions
in a Layered Earth: Journal of Geophysical Research, v. 83, no. B12, p. 5923-5928.
Fitterman, D.V., 1983, Modeling of Self-Potential Anomalies Near Vertical Dikes: Geophysics, v.
48, no. 2, p. 171-180.
Fitterman, D.Y-, 1983, Self-Potential Surveys Near Several Denver Water Department Dams:
U.S. Geological Survey Open-File Report 83-302, 25 p.
Furness, P. 1992, Modelling Spontaneous Mineralization Potentials with a New Integral Equation:
Journal of Applied Geophysics, v. 29, p. 143-155.
Furness, P., 1993, A Reconciliation of Mathematical Models for Spontaneous Mineralization
Potential: Geophysical Prospecting, v. 41, p. 779-790.
Keller, G.V., 1989, Electrical Properties, in R.S. Carmichael, editor, Practical Handbook of
Physical Properties of Rocks and Minerals: CRC Press, Boca Raton, Florida, p. 359-427.
Kilty, K.T., 1984, On the Origin and Interpretation of Self-Potential Anomalies: Geophysical
Prospecting, v. 32, p. 51-62.
Ogilvy, AA, Ayed, M.A., and Bogoslovsky, VA, 1969, Geophysical Studies of Water Leakage
From Reservoirs: Geophysical Prospecting, v. 17, no. 1, p. 36-62.
Ogilvy, AA., and Bogoslovsky, V.A., 1979, The Possibilities of Geophysical Methods Applied for
Investigating the Impact of Man on the Geological Medium: Geophysical Prospectiing, v.
27, p. 775-789.
Reznik, Y.M., 1990, Determination of Ground Water Paths Using Methods of Streaming
Potentials, in 1990 National Symposium on Mining, University of Kentucky, Lexington,
Kentucky, May 14-18,1990, p. 217-221.
Sato, M., and Mooney, H.M., 1960, The Electrochemical Mechanism of Sulfide Self-Potentials:
Geophysics, v. 25, p. 226-249.
Satyanarayana Murty, B.V., and Haricharan, P., 1985, Nomogram for the Complete
Interpretation of Spontaneous Potential Profiles Over Sheet-Like and Cylindrical Two-
Dimensional Sources: Geophysics, v. 50, p. 1127-1135.
Schiavone, D., and Quarto, R., 1984, Self-Potential Prospecting in the Study of Water
Movements: Geoexploration, v. 22, p. 47-58.
Sill, W.R., 1983, Self-Potential Modelling From Primary Flows: Geophysics, v. 48, no. 1, p. 76-86.
128.
-------
Stierman, D.J., 1984, Electrical Methods of Detecting Contaminated Groundwater at the
Stringfellow Waste Disposal Site, Riverside County, California: Environmental Geology
and Water Science, v. 6, no. 1, p. 11-20.
129.
-------
REFERENCES ON
SEISMIC GEOPHYSICAL METHODS
Ballantyne, EJ., Campbell, D.L., Menteraerier, S.H., and Wiggins, R., 1981, Manual of
Geophysical Hand-Held Calculator Programs, Volume 2: Society of Exploration
Geophysicists, Tulsa, Oklahoma.
Barker, R.D., 1990, Investigation of Ground Water Salinity by Geophysical Methods, in S.H.
Ward, editor, Geotechnical and Environmental Geophysics, in Investigations in
Geophysics No. 5, Volume II, Environmental and Groundwater: Society of Exploration
Geophysicists, Tulsa, Oklahoma, p. 245-251.
Brabham, PJ.,-and McDonald, RJ., 1992, Imaging a Buried River Channel in an Intertidal Area
of South Wales Using High-Resolution Seismic Techniques: Quarterly Journal of
Engineering Geology, v. 25, p. 177-182.
Bruehl, D.H., 1983, Use of Geophysical Techniques to Delineate Ground-Water Contamination,
in Proceeding of the Third National Symposium on Aquifer Restoration and Ground-
Water Monitoring, May 25-26,1983, Fawcett Center, Columbus, Ohio: National Water
Well Association, Worthington, Ohio, p. 295-300.
Burke, K.B.S., 1967, A Review of Some Problems of Seismic Prospecting for Groundwater in
Surficial Deposits, in L.W. Morley, editor, Mining and Groundwater Geophysics,
Economic Geology Report No. 26, Geological Survey of Canada: Department of Energy,
Mines and Resources, Ottawa, Canada, 569-579.
Carpenter, P J., Calkin, S.F., and Kaufmann, R.S., 1991, Assessing a Fractured Landfill Cover
Using Electrical Resistivity and Seismic Refraction Techniques: Geophysics, v. 56, no, 11,
p. 1896-1904.
Cooksley, J.W., 1992, General Discussion of Seismic Methods, in R. van Blaricom, compiler
Practical Geophysics II for the Exploration Geologist: Northwest Mining Association,
Spokane Washington, p. 275-311.
Crice, D.B., 1992, Application for Shallow Exploration Seisographs, in R. van Blaricom, compiler,
Practical Geophysics II for the Exploration Geologist: Northwest Mining Association,
Spokane Washington, p. 235-272.
Davies, KJ., Barker, R.D., and King, R.F., 1992, Application of Shallow Reflection Techniques
to Hydrogeology: Quarterly Journal of Engineering Geology, v. 25, p. 207-216.
Davies, KJ., and King, R.F., 1992, The Essentials of Shallow Reflection Data Processing:
Quarterly Journal of Engineering Geology, v. 25, p. 191-206.
Dobecki, T.L., 1979, Measurement of In-Situ Dynamic Properties in Relation to Geologic
Conditions, in Reviews in Engineering Geology, Volume IV: Geological Society of
America, p. 201-214.
130.
-------
Eaton, G.P., and Watkins, J.S., 1967, The Use of Seismic Refraction and Gravity Methods in
Hydrogeological Investigation, in L.W. Morley, editor,'Mining and Groundwater
Geophysics, Economic Geology Report No. 26, Geological Survey of Canada: Department
of Energy, Mines and Resources, Ottawa, Canada, 544-568.
Haeni, P.P., 1988, Applications of Seismic-Refraction Techniques to Hydrologic Studies:
Techniques of Water-Resource Investigations of the U.S. Geological Survey, Chapter D2,
Book 2, 86 p.
Hatherly, PJ., 1976, A Fortran IV Programme for the Reduction and Plotting of Seismic
Refraction Data Using the Generalized Reciprocal Method: Report of the Geologic
Survey of New South Wales, GS1976/236, p. 34.
Hill, LA., 1992, Field Techniques and Instrumentation in Shallow Seismic Reflection: Quarterly
Journal of Engineering Geology, v. 25, p. 183-190.
Hunter, J.H., 1981, Software Listing of Programs for Shallow Seismic Exploration Using Apple
Computers: Geological Survey of Canada Open-File Report 552.
King, R.F., 1992, High-Resolution Shallow Seismology: History, Principles and Problems:
Quarterly Journal of Engineering Geology, v. 25, p. 177-182.
King, W.C., Witten, AJ., and Read, G.D., 1989, Detection and Imaging of Buried Wastes Using
Seismic Propagation, Journal of Environmental Engineering: Americal Society of Civil
Engineers, v. 115, p. 527-540.
Kopsick, D.A., and Sander, T.W., 1983, Refinement of the Shallow Seismic Reflection Technique
in Determining Subsurface Alluvial Stratigrtaphy, in Proceeding of the Third National
Symposium on Aquifer Restoration and Ground-Water Monitoring, May 25-26,1983,
Fawcett Center, Columbus, Ohio: National Water Well Association, Worthington, Ohio,
p. 301-306.
Lankston, R.W., 1989, The Seismic Refraction Method: A Viable Tool for Mapping Shallow
Targets Into the 1990s: Geophysics, v. 54, p. 1535-1542.
Lankston, R.W., 1990, High-Resolution Refraction Seismic Data Acquisition and Interpretation,
in S.H. Ward, editor, Geotechnical and Environmental Geophysics, in Investigations in
Geophysics No. 5, Volume I, Review and Tutorial: Society of Exploration Geophysicists,
Tulsa, Oklahoma, p. 45-73.
Lankston, R.W., and Lankston, M.M., 1986, Obtaining Multilayer Reciprocal Times Through
Phantoming: Geophysics, v. 51, p. 45-49.
Lennox, D.H., and Carlson, V., 1967, Integration of Geophysical Methods for Groundwater
Exploration in the Prairie Provinces, Canada, in Morley, L.W., editor, Mining and
Groundwater Geophysics, Economic Geology Report No. 26, Geological Survey of
Canada: Department of Energy, Mines and Resources, Ottawa, Canada, p. 517-535.
Mooney, H.M., 1974, Seismic Shear Waves in Engineering, Journal of Geotechnical Engineers:
American Society of Civil Engineers, v. 98, no. SM7, p 667-691.
131.
-------
Mooney, H.M., 1984, Handbook of Engineering Geophysics, Volume 1, Seismic: Bison
Instruments, Minneapolis, Minnesota.
Muir, S.G., and Huggins, R., 1990, A Synopsis of Seismic Reflection Applications to
Geotechnical Engineering, Ground Water and Environmental Studies, in Geophysical
Applications in Engineering Geology and Ground Water, 3rd Annual Seminar
Proceeding, June 15-16,1990, Sacramento, California: Association of Engineering
Geologist, Sacramento Section.
Orndorff, R.C., Dodd, K., Bunnells, G.B., and Sakss, Y, 1989, Computer Programs Released as
U.S. Geological Survey Publications Through August 1989: U.S. Geological Survey Open-
File Report 89-681, 70 p.
Palmer, D., 1980, The Generalized Reciprocal Method of Seismic Refraction Interpretation:
Society of Exploration Geophysicists, Tulsa, p. 104.
Palmer, D. 1981, An Introduction to the Generalized Reciprocal Method of Seismic Refraction
Interpretation: Geophysics, v. 46, p. 1508-1518.
' Palmer, D., 1991, The Resolution of Narrow Low-Velocity Zones with the Generalized
Reciprocal Method: Geophysical Prospecting, v. 39, p. 1031-1060.
Steeples, D.W., and Miller, R.D., 1990, Seismic Reflection Methods Applied to Engineering,
Environmental, and Groundwater Problems, in S.H. Ward, editor, Geotechnical and
Environmental Geophysics, in Investigations in Geophysics No. 5, Volume I, Review and
Tutorial: Society of Exploration Geophysicists, Tulsa, Oklahoma, p. 1-30.
Underwood, J.E., Laudon KJ., and Laudon, T.S., 1984, Seismic and Resistivity Investigations
Near Norway, Michigan: Ground Water Monitoring Rewiew, v. 4, no. 4, Fall 1984, p. 86-
91.
Taylor, R.W., and Cherkauer, D.S., 1984, The Application of Combined Seismic and Electrical
Measurements to the Determination of Hydraulic Conductivity of a Lake Bed: Ground
Water Monitoring Review, v. 4, no. 4, Fall 1984, p. 78-85.
Whiteley, RJ., 1992, Comment on The Resolution of Narrow Low-Velocity Zones with the
Generalized Reciprocal Method1 by Derecke Palmer: Geophysical Prospecting, v. 40, p.
925-931.
132.
-------
REFERENCES ON
GRAVITY GEOPHYSICAL METHODS
Adams, J.M., and Hipze, WJ., 1990, The Gravity-Geologic Technique of Mapping Buried
Bedrock Topography, in S.H. Ward, editor, Geotechnical and Environmental Geophysics,
in Investigations in Geophysics No. 5, Volume III, Geotechnical: Society of Exploration
Geophysicists, Tulsa, Oklahoma, p. 99-105.
Arzi, 1975, Microgravity for Engineering Applications: Geophysical Prospecting, v. 23, p. 408-425.
Butler, D.K., 1984, Microgravimetic and Gravity Gradient Techniques for Detection of
Subsurface Cavities: Geophysics, v. 49, p. 1084-1096.
Carmichael, R.S., and Henry, G., 1977, Gravity Exploration for Groundwater and Bedrock
Topography in Glaciated Areas: Geophysics, v. 42, p. 850-859.
Dahlstrand, T.K., 1985, Applications of Microgravity Surveys to Subsurface Exploration, in
Proceedings of NWWA Conference on Surface and Borehole Geophysical Methods in
Ground Water Investigation, February 12-14, 1985, Fort Worth, Texas: National Water
Well Association, Worthington, Ohio, p. 85-101.
Dean, W.C., 1958, Frequency Analysis for Gravity and Magnetic Interpretations: Geophysics, v.
23, p. 97-127.
Dobrin, M.B., 1976, Introduction to Geophysical Prospecting (Third Edition): McGraw-Hill Book
Company, New York, New York, 630 p.
Eaton, G.P., and Watkins, J.S., 1967, The Use of Seismic Refraction and Gravity Methods in
Hydrogeological Investigation, in L.W. Morley, editor, Mining and Groundwater
Geophysics, Economic Geology Report No. 26, Geological Survey of Canada: Department
of Energy, Mines and Resources, Ottawa, Canada, p. 544-568.
Hart, W.S., and Muir, S.G., 1990, Gravity as a Tool for Engineering and Environmental Geology,
Applied Studies, in Geophysical Applications in Engineering Geology and Ground Water,
3rd Annual Seminar Proceeding, June 15-16,1990, Sacramento, California: Association of
Engineering Geologist, Sacramento Section.
Hinze, WJ., 1988, Gravity and Magnetic Methods Applied to Engineering and Environmental
Problems, in Proceedings of the Symposium on the Application of Geophysics to
Engineering and Environmental Problems (SAGEEP) March 13-16, 1989: Society of
Engineering and Mineral Explorationm Geophysicists, Golden, Colorado, p. 1-107.
Ibrahim, A., and Hinze, WJ., 1972, Mapping Buried Bedrock Topography with Gravity: Ground
Water, v. 10, p. 18-23.
Kelly, W.E., and Mares, S., editors, 1993, Applied Geophysics in Hydrogeological and
Engineering Practice, in Developments in Water Science, v. 44: Elsevier Science
Publishers B.V., New York, New York, 289 p.
133.
-------
Kick, J.F., 1989, Landfill Investigations in New England Using Gravity Methods, in Proceedings
of tfie Symposium on the Application of Geophysics to'' Engineering and Environmental
Problems (SAGEEP) March 13-16, 1989: Society of Engineering and Mineral Exploration
Geophysicists, Golden, Colorado, p. 339-353.
Lennox, D.H., and Carlson, V., 1967, Integration of Geophysical Methods for Groundwater
Exploration in the Prairie Provinces, Canada, in L.W. Morley, editor, Mining and
Groundwater Geophysics, Economic Geology Report No. 26, Geological Survey of
• Canada: Department of Energy, Mines and Resources, Ottawa, Canada, p. 517-535. .
Richard, B.H., and Wolfe, P.H., 1990, Gravity as a Tool to Delineate Buried Valleys, in
Proceedings of the Symposium on the Application of Geophysics to Engineering and
Environmental Problems (SAGEEP) March 13-16,1989: Society of Engineering and
Mineral Explorationm Geophysicists, Golden, Colorado, p. 59-105.
Roberts, R.L., 1989, A Multi-Technique Geophysical Approach to the Study of Landfills and
Potential Ground Water Contamination, Masters Thesis: Purdue University, 247 p.
Roberts, R.L., Hinze, W J., and Leap, D.I., 1989, A Multi-Technique Geophysical Approach to
Landfill Investigations, in Proceedings on the Third National Outdoor Action Conference
on Aquifer Restoration, Ground Water Monitoring and Geophysical Methods, May 22-25,
1989, Orange County Convention Center, Orlando, Florida: National Water Well
Association, Dublin, Ohio, p. 797-811.
Sandberg, S.K., and Hall, D.W., 1990, Geophysical Investigation of an Unconsolidated Coastal
Plain Aquifer System and the Underlying Bedrock Geology in Central New Jersey, in S.H.
Ward, editor, Geotechnical and Environmental Geophysics, in Investigations in
Geophysics No. 5, Volume II, Environmental and Groundwater: Society of Exploration
Geophysicists, Tulsa, Oklahoma, p. 311-320.
Telford, W.M., Geldart, L.P. and Sheriff, R.E., 1990, Applied Geophysics (Second Edition):
Cambridge University Press, New York, New York, 770 p.
West, R.E., 1992, The Land Gravity Exploration Method, in R. van Blaricom, Practical
Geophysics II for the Exploration Geologist, compiler: Northwest Mining Association,
Spokane Washington, p. 177-233.
Wolfe, P J., and Richard, B.H., 1990, Geophysical Studies of Cedar Bogs, in S.H. Ward, editor,
Geotechnical and Environmental Geophysics, in Investigations in Geophysics No. 5,
Volume II, Environmental and Groundwater: Society of Exploration Geophysicists, Tulsa,
Oklahoma, p. 281-288.
Zohdy, A.A.R., Eaton, G.P., and Mabey, D.R., 1974, Application of Surface Geophysics to
Ground-Water Investigations: Techniques of Water-Resource Investigations of the U.S.
Geological Survey, Book 2, Chapter Dl, 116 p.
134.
-------
REFERENCES ON
MAGNETIC GEOPHYSICAL METHODS
Allen, R.P., and Rogers, B.A., 1989, Geophysical Surveys in Support of a Remedial
Investigation/Feasibility Study at the Municipal Landfill in Metamora, Michigan, in
Proceedings on the Third National Outdoor Action Conference on Aquifer Restoration,
Ground Water Monitoring and Geophysical Methods, May 22-25, 1989, Orange County
Convention Center, Orlando, Florida: National Water Well Association, Dublin, Ohio, p.
1007-1020.
Breiner, S., 1973, Applications Manual for Portable Magnetometers: EG&G Geometries,
Sunnyvale, California, 58 p.
Breiner, S., 1992, Applications for Portable Magnetometers, in R. van Blaricom, compiler,
Practical Geophysics II for the Exploration Geologist: Northwest Mining Association,
Spokane Washington, p. 313-345.
DeReamer, J., and Pierce, D., 1990, Geophysical Investigation for Buried Drums: A Case Study,
in Geophysical Applications in Engineering Geology and Ground Water, 3rd Annual
Seminar Proceeding, June 15-16,1990, Sacramento, California: Association of
Engineering Geologist, Sacramento Section.
Fowler, J.W., and Pasicznyk, D.L., 1985, Magnetic Survey Methods Used in the Initial
Assessment of a Waste Disposal Site, in Proceedings of NWWA Conference on Surface
and Borehole Geophysical Methods in Ground Water Investigation, February 12-14,1985,
Fort Worth, Texas: National Water Well Association, Worthington, Ohio, p. 267-280.
Hinze, WJ., 1988, Gravity and Magnetic Methods Applied to Engineering and Environmental
Problems, in Proceedings of the Symposium on the Application of Geophysics to
Engineering and Environmental Problems (SAGEEP) March 13-16,1989: Society of
Engineering and Mineral Explorationm Geophysicists, Golden, Colorado, p. 1-107.
Telford, W.M., Geldart, L.P. and Sheriff, R.E., 1990, Applied Geophysics (Second Edition):
Cambridge University Press, New York, New York, 770 p.
Zohdy, A.A.R., Eaton, G.P., and Mabey, D.R., 1974, Application of Surface Geophysics to
Ground-Water Investigations: Techniques of Water-Resource Investigations of the U.S.
Geological Survey, Book 2, Chapter Dl, 116 p.
135.
-------
REFERENCES ON
GROUND PENETRATING RADAR GEOPHYCICAL METHOD
*
Allen, R.P., and Seelen, M.A., 1992, The Use of Geophysics in the Detection of Buried Toxic
Agents at a U.S. Military Installation, in D.M. Nielsen and M.N. Sara, editors, Current
Practices in Ground Water And Vadoze Zone Investigations, ASTM STP-1118: American
Society for Testing and Materials, Philadelphia, Pennsylvania, p. 59-68.
Benson, R.C., Glaccum, R.A., and Noel, M.R., 1984, Geophysical Techniques for Sensing Buried
Wastes and Waste Migration, USEPA Contract No. 68-03-3053: Environmental
Monitoring Systems Laboratory, Office of Research and Development, U.S.
Environmental Protection Agency, Las Vegas, Nevada, 236 p.
Beres, Jr., M., and Haeni, F.P., 1991, Application of Ground-Penetrating Radar Methods in
Hydrogeologic Studies: Ground Water, v. 29, p. 375-386.
Boucher, R., and Galinovsky, L., 1989, RADAN 3.0, Geophysical Survey Systems, Inc., North
Salem, New Hampshire.
Cook, J.C., 1975, Radar Transparencies of Mine and Tunnel Rocks: Geophysics, v. 40, p, 865-885.
Coon, J.B., Fowler, J.C., and Schafers, CJ., 1981, Experimental Uses of Short-Pulse Radar in
Coal Seams: Geophysics, v. 46, p. 1163-1168.
Daniels, J.D., 1989, Fundamental of Ground Penetrating Radar, in Proceedings of the
Symposium on the Application of Geophysics to Engineering and Environmental
Problems (SAGEEP) March 13-16,1989: Society of Engineering and Mineral Exploration
Geophysicists, Golden, Colorado, p. 62-142.
Davis, J.L., and Annan, A.P., 1989, Ground-Penetrating Radar for High-Resolution Mapping of
Soil and Rock Stratigraphy: Geophysical Prospecting, v. 37, p. 531-551.
Davis, J.L., Killey, R.W.D., Annan, A.P., and Vaughan, CJ., 1984, Surface and Borehole Ground-
Penetrating Radar Surveys for Mapping Geologic Structure, in Proceeding of NWWA
Conference on Surface and Borehole Geophysical Methods in Ground Water
Investigations, San Antonio, Texas: National Water Well Association, p. 681-712.
Filler, D.M., and Kuo, S.S., 1989, Subsurface Cavity Exploration Using Non-Distructive
Geophysical Methods, in Proceedings on the Third National Outdoor Action Conference
on Aquifer Restoration, Ground Water Monitoring and Geophysical Methods, May 22-25,
1989, Orange County Convention Center, Orlando, Florida: National Water Well
Association, Dublin, Ohio, p. 827-840.
Fisher, E., McMechan, G.A., and Annan, A.P., 1992, Aquisition and Processing of Wide-
Aperature Ground-Penetrating Radar Data: Geophysics, v. 57, p. 495-504.
Hennon, K. 1990, Zillion Uses of Ground Penetrating Radar, in Geophysical Applications in
Engineering Geology and Ground Water, 3rd Annual Seminar Proceeding, June 15-16,
1990, Sacramento, California: Association of Engineering Geologist, Sacramento Section.
136.
-------
Morey, R.M., 1974, Continous Subsurface Profiling by Impulse Radar, in Proceeding of
Engineering Foundations Conference on Subsurface Explorations for Underground
Excavations and Heavy Construction, Henniker, New Hampshire, p. 213-232.
Olhoeft, G.R., 1988, Selected Bibliography on Ground Penetrating Radar, in Proceeding on
Symposium on Application of Geophysics in Engineering and Environmental Problems:
Society of Engineering and Mineral Exploration Geophysicists, Golden, Colorado, p. 463-
520.
Underwood, I.E., and Eales, J.W., 1984, Detecting a Buried Crystalline Waste Mass with Ground
Penetrating Radar, in D.M. Nielsen and M. Curl, editors, NWWA/EPA Conference on
Surface and Borehole Geophysical Methods in Ground Water Investigations: National
Water Well Association, Worthington, Ohio, p. 654-665.
Wright, D.L., Olhoeft, G.R., and Watts, R.D., 1984, Ground Penetrating Radar Studies in Cape
Cod, in D.M. Nielsen and M. Curl, editors, NWWA/EPA Conference on Surface and
Borehole Geophysical Methods in Ground Water Investigations: National Water Well
Association, Worthington, Ohio, p. 368-382.
137.
-------
REFERENCES ON
BOREHOLE GEOPHYSICAL METHODS
Alger, R.P., 1966, Interpretation of Electric Logs in Fresh Water Wells in Unconsolidated
Formations, in Transactions of the Society of Professional Well Log Analysts, Seventh
Annual Logging Symposium, May 9-11, Tulsa, Oklahoma, p. CC1-CC23.
Algers, R., and Harrison, C, 1988, Improved Fresh Water Assessment in Sand Aquifers, in
Proceedings of the Second National Outdoor Action Conference on Aquifer Restoration,
Ground Water Monitoring and Geophysical Methods, May 23-26, 1988, Las Vegas,
Nevada: National Water Well Association, Dublin, Ohio, p. 939-967.
Barker, R.D., and Worthington, P.E., 1973, Some Hydrogeophysical Properties of the Bunter
Sandstone of Northwest England: Geoexploration, v. 11, p. 151-170.
Biella, G., Lozej, A., and Tabacco, I., 1983, Experimental Study of Some Hydrogeophysical
Properties of Unconsolidated Porous Media: Ground Water, p. 741-751.
Brock, J., 1986, Applied Open-Hole Log Analysis, in Contributions in Petroleum Geology and
Engineering, Volume 2: Gulf Publications, Houston, Texas, 284 p.
Bums, D.R., 1990, Acoustic Waveform Logs and the In-Situ Measurement of Permeablity, in F.L.
Paillet and W.R. Saunders, editors, Geophysical Applications for Geotechnical
Investigations, STP-1101: American Society for Testing and Materials, Philadelphia,
Pennsylvania, p 65-78.
Collier, H.A., and Alger, R.P., 1988, Recommendation for Obtaining Valid Data From Borehole
Geophysical Logs, in Proceedings of the Second National Outdoor Action Conference on
Aquifer Restoration, Ground Water Monitoring and Geophysical Methods, May 23-26,
1988, Las Vegas, Nevada: National Water Well Association, Dublin, Ohio, p. 897-923.
Croft, M.G., 1971, A Method of Calculating Permeability from Electric Logs, in U.S. Geological
Survey Research 1971: U.S. Geological Survey Professional Paper 750-B, p. B265-B269.
Crowder, R.E., Lo Coco, JJ., and Yearsley, E.N., 1991, Application of Full Waveform Borehole
Sonic Logs to Environmental and Subsurface Engineering Investigations, in Proceedings
of the Symposium on the Application of Geophysics to Environmental and Engineering
Problems, March 10-14,1991, Knoxville, Tennessee: Society of Exploration Geophysicists,
13 p.
Daniels, JJ., and Keys, W.S., 1990, Geophysical Well Logging for Evaluating Hazardous Waste
Sites, in S.H. Ward, editor, Geotechnical and Environmental Geophysics, in Investigations
in Geophysics No. 5, Volume I, Review and Tutorial: Society of Exploration
Geophysicists, Tulsa, Oklahoma, p. 263-285.
Deluca, RJ., and Buckley, B.K., 1985, Borehole Logging to Delineate Fractures in a
Contaminated Bedrock Aquifer, in Proceedings of NWWA Conference on Surface and
Borehole Geophysical Methods in Ground Water Investigation, February 12-14, 1985,
Fort Worth, Texas: National Water Well Association, Worthington, Ohio, p. 387-397.
138.
-------
Desai, K.P., and Moore, E.J., 1969, Equivalent NaCl Determination from Ionic Concentrations:
The Log Analyst, May-June, 1969, p. 12-21.
Dresser Atlas, 1975, Log Interpretation Fundamentals, Houston, Texas.
Driscoll, F.G., 1987, Ground Water and Wells (2nd Edition): Johnson Division, Saint Paul,
Minnesota, 1089 p.
Engineering Enterprises, Inc., 1985, Log Interpretation Workshop for U.S. EPA Region IX,
Norman, Oklahoma, 89 p.
Griffiths, D., 1976, Application of Electrical Resistivity Measurements for the Determination of
Porosity and Permeabilty in Sandstones: Geoexploration, v. 14, p. 207-219.
Guo, Y.A., 1986, Estimation of TDS in Sand Aquifer Water Through Resistiviy Log: Ground
Water, v. 24, no. 5, p. 598-600.
Hearst, J.R., and Nelson, P.W., 1985, Well Logging of Physical Properties: McGraw-Hill, New
York, New York.
Hess, A.E., Paillet, F.L., 1990, Application of the Thermal-Pulse Flowmeter in the Hydraulic
Characterization of Fractured Rocks, in F.L. Paillet and W.R. Saunders, editors,
Geophysical Applications for Geotechnical Investigations, STP-1101: American Society for
Testing and Materials, Philadelphia, Pennsylvania, p 99-112.
Howard, K.W.F., 1990a, Geophysical Well Logging Methods for Detection and Characterization
of Fractures in Hard Rocks, in S.H. Ward, editor, Geotechnical and Environmental
Geophysics, in Investigations in Geophysics No. 5, Volume I, Review and Tutorial:
Society of Exploration Geophysicists, Tulsa, Oklahoma, p. 287-307.
Howard, K.W.F., 1990b, The Role of Well Logging in Contaminant Transport Studies, in S.H.
Ward, editor, Geotechnical and Environmental Geophysics, in Investigations in
Geophysics No. 5, Volume II, Environmental and Groundwater: Society of Exploration
Geophysicists, Tulsa, Oklahoma, p. 289-301.
Huntley, D., 1986, Relations Between Permeability and Electrical Resistivity in Granular
Aquifers: Ground Water, v. 24, no. 4, p. 466-474.
Jones, P.H., and Buford, T.B., 1951, Electrical Logging Applied to Ground Water Exploration:
Geophysics, v. XVI, no. 1, p. 115-139.
Jorgensen, D.G., 1989, Using Geophysical Logs to Estimate Porosity, Water Resistivity, and
Intrinsic Permeability: U.S. Geological Survey Water-Supply Paper 2321, 24 p.
Jorgensen, D.G., 1990, Estimating Water Quality From Geophysical Logs, in F.L. Paillet and
W.R. Saunders, editors, Geophysical Applications for Geotechnical Investigations, STP-
1101: American Society for Testing and Materials, Philadelphia, Pennsylvania, p. 47-64.
139.
-------
Keys, W.W., 1967, Borehole Geophysics as Applied to Groundwater, in L.W. Morley, editor,
Mining and Groundwater Geophysics, Economic Geolpgy Report No. 26, Geological
Survey of Canada: Department of Energy, Mines and Resources, Ottawa, Canada, 598-
614.
Keys, W.S., 1989, Borehole Geophysics Applied to Ground Water Investigations: National Water
Well Association, Dublin, Ohio, 313 p.
Keys, W.S., and MacCary, L.M., 1971, Application of Borehole Geophysics to Water-Resource
Investigations: U.S. Geological Survey Techniques of Water-Resource Investigations,
Book 2, Chapter El, 126 p.
Kwader, T., 1985, Resistivity-Porosity Cross Plots for Determining In-Situ Formation Water
Quality-Case Examples, in Proceedings of NWWA Conference on Surface and Borehole
Gepphysical Methods in Ground Water Investigation, February 12-14, 1985, Fort Worth,
Texas: National Water Well Association, Worthington, Ohio, p. 415-424.
Kwader, T, 1986, The Use of Geophysical Logs for Determining Formation Water Quality:
Ground Water, v. 24, no. 1, p. 11-15.
Labo, J., 1986, A practical Introduction to Borehole Geophysics, Geophysical References Volume
2: Society of Exploration Geophysicists, Tulsa, Oklahoma, 330 p.
Lynch, EJ., 1962, Formation Evaluation: Harper and Row, Publishers, New York, New York, 422
P-
MacCary, L.M., 1978, Interpretation of Well Logs in a Carbonate Aquifer: U.S. Geological
Survey, Water-Resources Investigatons Report 78-88.
Merin, I.S., 1989, Characterization of Fractures in Devonian Siltsones, Northern Appalachian
Plateau: Implications for Ground Water Flow, in Proceedings on the Third National
Outdoor Action Conference on Aquifer Restoration, Ground Water Monitoring and
Geophysical Methods, May 22-25,1989, Orange County Convention Center, Orlando,
Florida: National Water Well Association, Dublin, Ohio, p. 921-934.
Merkel, R.H., 1979, Well Log Formation Evaluation, Continuing Education Course Notes, Series
No. 14: American Association of Petroleum Geologist, 82 p.
Moore, E J., 1966, A Graphical Description of New Methods for Determining Equivalent NaCl
Concentrations From Chemical Analysis, in Transactions of the Society of Professional
Well Log Analysts, Seventh Annual Logging Symposium, May 9-11, Tulsa, Oklahoma, p.
M1-M34.
Morin, R.H., Hess, A.E., and Paillet, F.L., 1988, Determing the Distribution of Hydraulic
Conductivity in a Fractured Limestone Aquifer by Simultaneous Injection and
Geophysical Logging: Ground Water, v. 26, p. 587.
Mwenifumbo, CJ., 1993, Borehole Geophysics in Environmental Mining: Canadian Institute of
Mining Bulletin, v. 86, no. 966, January 1993, p. 43-49.
140.
-------
Ogbe, D., and Bassiouni, Z., 1978, Estimation of Aquifer Permeabilities From Electric Logs: The
Log Analyst, September-October, 1978, p. 21-27. :
Paillet, F.L., and Saunders, W.R., editors, Geophysical Applications for Geotechnical
Investigations, ASTM STP-1101: American Society for Testing and Materials,
Philadelphia, Pennsylvania, 112 p.
Roscoe Moss Company, 1990, Handbook of Ground Water Development: John Wiley and Sons,
New York, New York, 493 p.
Sciacca, J., 1989, Operational and Quality Assurance Considerations for Borehole Geophysical
Logging in Hydrogeologic Investigations, in Proceedings on the Third National Outdoor
Action.Conference on Aquifer Restoration, Ground Water Monitoring and Geophysical
Methods, May 22-25,1989, Orange County Convention Center, Orlando, Florida:
National Water Well Association, Dublin, Ohio, p. 891-907.
Schlumberger, 1972a, Log Interpretation, Volume I, Principles, New York, New York, 112 p.
Schlumberger, 1972b, Log Interpretation Charts, New York, New York, 92 p;
Schlumberger, 1974, Log Interpretation, Volume II, Applications, New York, New York, 116 p.
Schlumberger, 1987, Log Interpretation, Principles/Applications, New York, New York, 198 p.
Snelgrove, F.B., and McNeill, J.D., 1985, Theory and Design Considerations of a Borehole
Electromagnetic Conductivity Probe, in Proceedings of NWWA Conference on Surface
and Borehole Geophysical Methods in Ground Water Investigation, February 12-14,1985,
Fort Worth, Texas: National Water Well Association, Worthington, Ohio, p. 339-354.
Spencer, S.M., 1985, Stratigraphic Determination and Correlations Based on Borehole
Geophysics, in Proceedings of NWWA Conference on Surface and Borehole Geophysical
Methods in Ground Water Investigation, February 12-14,1985, Fort Worth, Texas:
National Water Well Association, Worthington, Ohio, p. 326-338.
Stegner, R., and Becker, A., 1988, Borehole Geophysical Methodolgy: Analysis and Comparison
of New Technologies for Ground Water Investigations, in Proceedings of the Second
National Outdoor Action Conference on Aquifer Restoration, Ground Water Monitoring
and Geophysical Methods: National Water Well Association, Dublin, Ohio, p. 987-1011.
Stowell, J.R., 1989, An Overview of Borehole Geophysical Methods for Solving Engineering an
Environmental Problems, in Proceedings on the Third National Outdoor Action
Conference on Aquifer Restoration, Ground Water Monitoring and Geophysical
Methods, May 22-25,1989, Orange County Convention Center, Orlando, Florida:
National Water Well Association, Dublin, Ohio, p. 871-890.
Taylor, K, Hess, J., and Mazzela, A., 1989, Field Evaluation of a Slim-Hole Borehole Inductions
Tool: Ground Water Monitoring Review, v. IX, no. 1, p. 100-104.
Turcan, A.N., 1962, Estimating Water Quality from Electrical Logs: U.S. Geologic Survey
Professional Paper 450-C, p. C135-C136.
141.
-------
Turcan, A.N., 1966, Calculation of Water Quality from Electrical Logs, Theory and Practice,
Water Resource Pamphlet No. 19: Department of Conservation: Louisiana Geological
Survey, Baton Rouge, Louisiana, 23 p.
Welenco, Inc., Water Well Geophysical Logs (3rd Edition), Bakersfield, California, 59 p.
Worthington, P.P., 1976, Hydrogeophysical Equivalence of Water Salinity, Porosity and Matrix
Conduction in Arenaceous Aquifers: Ground Water, v. 14, no. 4, p. 224-232.
Worthington, P.P., and Barker, R.D., 1972, Methods for the Calculation of True Formation
Factors in the Bunter Sandstone of Northwest England: Engineering Geology, v. 6, p.
213-228.
Yearsley, E.N., and Crowder, R.F., 1990, State-of-the-Art Borehole Geophysics Applied to
Hydrogeology, in Canadian/American Conference on Hydrogeology, Calgary, Canada,
September 18-20, 1990, 17 p.
Yearsley, E.N., and Crowder, R.F., 1991, State-of-the-Art Borehole Geophysics Applied to
Hydrogeology, in Short Course, Borehole Geophysics in Environmental and Engineering
Investigations, June 17-18,1991, Emeryville, California: COLOG Inc., Golden, Colorado,
17 p.
Yearsley, E.N., Crowder, R.F., and Irons, L.A., 1991, Monitoring Well Completion Evaluation
with Borehole Geophysical Density Logging: Ground Water Monitoring Review, v. 11, no.
1, Winter 1991, p. 103-111.
142.
-------
V. LIST OF ABBREVIATIONS
A
B
°C
cgs
cm
E
3
H
Hz
°K
kJ
L
m
mg
mg/L
raks
mho
mraho/m
mm
mol.
mS
mS/m
mV
Pa
s
S
T
v
P.
a
«t>
a
AtS/cm
/Ltmho/cm
/xmho/m
ampere
magnetic field
degrees Celsius
centimeters-grams-seconds
centimeter
electrical field strength
Faraday's constant
magnetic field strength
Hertz = cycles / second
degrees Kelvin
kilojoules
liter
meter
milligram
milligrams / Liter
meters-kilograms-seconds
I/ohms = 1/ii
millimhos / meter
millimeter
mole
milliSiemen
milliSiemens / meter
milliVolt
Pascal
second
longitudinal conductance
transverse resistance
volts
resistivity
conductivity
phase difference between E and H
ohm
magnetic permeability
magnetic field
microSiemen
microSiemens / centimeter
micromhos / centimeter
micromhos / meter
143.
------- |