ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF ENFORCEMENT
EPA-330/1-79-OO5
REMOTE SENSING STUDY
SOLID/LIQUID WASTE DISPOSAL SITES
SAN FRANCISCO BAY AREA OF CALIFORNIA
Second in a Series:
Update Investigations of the 1977 Study
ATIONAL ENFORCEMENT INVESTIGATIONS CENTER
DENVER. COLORADO
AUGUST 1979
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF ENFORCEMENT
EPA-330/1-79-005
REMOTE SENSING STUDY
SOLID/LIQUID WASTE DISPOSAL SITES
SAN FRANCISCO BAY AREA OF CALIFORNIA
Second in a Series
UPDATE INVESTIGATIONS OF THE 1977 STUDY
August 1979
NATIONAL ENFORCEMENT INVESTIGATIONS CENTER
Denver, Colorado
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CONTENTS
I INTRODUCTION 1
II SUMMARY AND CONCLUSIONS 3
III RESULTS OF INVESTIGATION 6
APPENDICES
A Concord Fault, Miscellaneous Field Studies, Map MF 505
B Frizzel1-Brown, Green Valley Fault, Miscellaneous Field
Studies, Map MF 743
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FIGURES
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
Location Map, San Francisco
Section of the Mil pitas 7.5
Wastewater Ponds, Mil pitas,
Section of the Oakland West
Bay Area, California
Minute Chart ....
California
7.5 Minute Chart . .
7
8
9
11
12
Yellow Stained Industrial Site, Emeryville, Calif.
Section of the Richmond 7.5 Minute Chart 13
Containment Pond, Berkeley, California 14
Open Disposal Site, Richmond, California 15
Liquid Waste Disposal Site, Richmond, California 16
Sections of the Richmond and San Quentin 7.5 Minute Charts ... 18
Waste Disposal Ponds,
General Refuse Dump,
Open Refuse Disposal
Solid Waste Disposal
Water Canal Segments.
Liquid Waste Holding
, Richmond, California 19
Richmond, California 20
Site, Richmond, California 21
Site, Contra Costa County, CA 22
, Richmond and Contra Costa County, CA . . . 24
Ponds, Richmond, California 25
Oil Sludge Holding Pond, Richmond, California 26
Section of the Port Chicago 7.5 Minute Chart 28
Waste Liquid Pond, Vine Hill Area, California 29
Vine Hill Disposal Site, Martinez, California 30
Sections of the
Industrial Tank
Benicia,
Industrial
Benicia,
Industrial
Benicia,
Industrial
Benicia,
Industrial
Benicia,
Industrial
Benicia,
Industrial
Benicia,
Industrial
Benicia,
33
CA -
Tank
CA -
Tank
CA -
Tank
Benicia and Port Chicago 7.5 Minute Charts . .
Environmental Corp., Benicia Disposal Site,
California. View from North to South
Tank Environmental Corp., Benicia Disposal Site,
View from Northeast to Southeast
Environmental Corp., Benicia Disposal Site,
View from North Northwest to South Southeast .
Environmental Corp., Benicia Disposal Site,
View from Southwest to Northeast 37
Environmental Corp., Benicia Disposal Site,
CA View from West to East
Tank Environmental Corp., Benicia Disposal Site,
CA View from West Southwest to East Northeast . . .
Tank Environmental Corp., Benicia Disposal Site,
CA View from North Northwest to South Southeast . .
Tank Environmental Corp., Benicia Disposal Site,
CA View from Southwest to Northeast, Southern
End of the Site
Industrial Tank Environmental Corp., Benicia Disposal Site,
Benicia, CA View from West Southwest to East Northeast,
Middle Area
Industrial Tank Environmental Corp., Benicia Disposal Site,
CA View from North to South Middle Area
Tank Environmental Corp., Benicia Disposal Site,
CA View from North Northeast to South Southeast,
Area
Benicia,
Industrial
Benicia,
Northern
34
35
36
38
39
40
41
43
44
45
Exxon Refinery Wastewater Treatment Plant, Benicia, CA. ,
Northwest Section 46
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FIGURES (Cont'd)
34 Exxon Refinery Wastewater Treatment Plant, Benicia, CA.,
Southeast Section 47
35 Section of the Antioch North, 7.5 Minute Chart 49
36 Liquid Waste Holding Pond, Pittsburg Point, Pittsburg, CA . . . 50
37 Liquid Waste Holding Pond, Adjacent to South shore of New
York Slough, Pittsburg, California 51
38 Wastewater Treatment Plant, Pittsburg, California 52
39 Holding Ponds, Wastewater Treatment Plant, Pittsburg, CA . . . . 53
40 Large Holding Ponds, Wastewater Treatment Plant,
Pittsburg, California 55
41 Natural Holding Ponds, Wastewater Treatment Plant,
Pittsburg, California 56
42 Section of the Jersey Island 7.5 Minute Chart 58
43 Sections of the Honker Bay and Antioch North Charts 59
44 Waste Disposal Site, U.S. Steel Corp., Pittsburg Works,
Pittsburg, California 60
45 Coal Storage Facility, Pittsburg, California 62
46 Northern Area of the U.S. Steel Corp., Pittsburg Works,
Pittsburg, California 63
47 Southern Area, Open Disposal Site,,U.S. Steel Corp.,
Pittsburg, California 64
48 Southeastern Area, Open Disposal Site, U.S. Steel Corp,
Pittsburg Works, Pittsburg, California 65
49 Northwestern Area, Open Disposal Site, U.S. Steel Corp.,
Pittsburg Works, Pittsburg, California 66
50 Western Area, Open Disposal Site, U.S. Steel Corp.,
Pittsburg Works, Pittsburg, California 67
51 Northern Area, Open Disposal Site, U.S. Steel Corp.,
Pittsburg Works, Pittsburg, California 68
52 Northeastern Area, Open Disposal Site, U.S. Steel Corp.,
Pittsburg Works, Pittsburg, California 69
53 Sections of the Glen Ellen and Petaluma River. 7.5 Minute
Charts 71
54 Solid Waste Disposal Site, Petaluma Area, California 72
55 Rural Disposal Site, Petaluma Area, California 73
56 Section of the Asti 7.5 Minute Chart 74
57 Small Manufacturing Facility, Asti Area, California 76
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I. INTRODUCTION
An aerial survey of solid and liquid waste disposal/holding
facilities in the greater San Francisco Bay area was conducted on
March 13 and 14, 1979. The survey area consisted of discrete sites
from San Jose northward to Asti, near Cloverdale, eastward to Antioch,
and then westward through Suisun Bay to Richmond and Oakland. The
National Enforcement Investigations Center (NEIC), U.S. Environmental
Protection Agency (EPA) conducted this survey at the request of the
Hazardous Materials Management Section of the California State Depart-
ment of Health Services and EPA Region IX.
The purpose of this survey was to document the presence of solid
and liquid waste disposal/holding sites within preselected industrial
facilities. The presence of casual disposal sites, typical solid
waste disposal sites (sanitary land fills) and state-licensed hazard-
ous waste disposal facilities were also documented. The remote sensing
data were also to be analyzed to detect any illegal or promiscuous
dumping within industrial facilities or at remote sites and to detect
unauthorized disposal of liquid waste at solid waste disposal sites.
Also any visible environmental effects of disposal practices were to
be documented, such as surface run-off patterns, surface leachate
flow, impoundment leakage and damaged or stressed vegetation in the
immediate environs of disposal sites due to liquid leachate and the
escape of volatile (gaseous) substances.
This survey was the second in a series of studies of the major
disposal facilities in the greater Bay area. The first survey was
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conducted from June 1977 through February 1978. Most of the major
facilities covered in the first survey were also overflown during the
second. For the facilities exposed to the double coverage, direct
comparisons of the respective photographic data were to be conducted
for geographic, physical, hydrologic, optical, and other environmental
characteristics.
These studies were conducted under the authority of the Resource
Conservation and Recovery Act (RCRA; PL 94-580) which requires the
periodic inventory and continuing surveillance of industrial, commer-
cial, municipal, and private facilities in addition to remote sites
where hazardous wastes are disposed. State of California personnel
have and will continue to use the results of these surveys to perform
on-site investigation of each facility as deemed appropriate.
The names of some facilities were provided by a State of California
Department of Health employee onboard the aircraft during this survey.
NEIC employed standard aerial reconnaissance and remote sensing
techniques to conduct the survey. Color aerial photographs, exposed
with a 70 mm hand-held camera, were obtained from a light aircraft
flying about 2,000 feet above ground level. The color photos were
basically two types. One type was a true-color film (red through
blue light exposure) and the other was a false-color infrared film
exposed with green, red and near-infrared light. The blue light nor-
mally used in true-color photography was subtracted by a optical filter.
The aerial photographs were recorded on a color-reversal film which
produces color transparencies. The transparencies were used during
data analysis in the laboratory. The black-and-white photographs in
this report were reproduced from the color transparencies.
* EPA Report No. EPA-330/3-77-002, December 1977 Remote Sensing
Study, Solid/Liquid Waste Disposal Sites San Francisco Bay Area
at California; coverage of Salinas, CA area included in EPA Report
No. EPA-330/1-78-004, August 1978, Remote Sensing Study, Solid/
Liquid Waste Disposal Sites, Greater Los Angeles Area, California,
pp. 172-183.
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II. SUMMARY AND CONCLUSIONS
An aerial survey of numerous solid and liquid waste disposal/
holding facilities was conducted in the greater San Francisco Bay
area. The survey area consisted of discrete sites extending from the
vicinity of San Jose north to Asti, near Cloverdale, east to Antioch,
and westward through Suisun Bay to Richmond and Oakland. The survey
area was divided into subareas corresponding to the respective USGS
7.5 minute charts that contain the geographic locations of the discrete
sites. The location of each subarea is shown in Figure 1 (Section III).
This survey was conducted as a followup to the one performed in 1977.
The aerial survey photographic films were interpreted and analyzed
in the NEIC Remote Sensing Laboratory. Any significant observations
of the disposal of solid and liquid waste material were reported.
Also, any significant (visible) environmental effects in the immediate
environs of a disposal site were reported.
The most significant findings concerned the hazardous waste dis-
posal sites, Vine Hill, Baker and Benicia Sites, operated by the Indus-
trial Tank Environmental Corporation in Martinez and Benicia, California.
The aerial imagery indicated that the waste liquid in the holding ponds
of the Vine Hill Site was possibly seeping out onto a relatively flat
denuded area immediately to the east. The color of the liquid in the
denuded area and in the holding ponds was identical.
The Baker Site is a Class 1 disposal site, which means that the
State of California has issued a license to permit disposal of hazard-
ous liquid waste. It is located adjacent to Pacheco Creek which flows
directly into Suisun Bay. A geological report indicates that the
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Avon Segment of the Concord Fault passes directly under the northern-
most pond of this site and through the denuded area along the east
site of Vine Hill Site [Figure Al or Appendix A]. According to the
California waste disposal regulation, a Class 1 disposal site cannot
be located over a geologic fault. The proximity of the fault to
these two disposal sites creates a potential hazard to the environment.
The Benicia Disposal Site is on a hill north of the city of Benicia.
This disposal site (Class 1) contains at least 54 liquid waste ponds
of varied colors. Some of the earthen dams forming the ponds showed
many more indications of seepage and/or over-spillage of the dark-colored
liquid waste than was present in the 1977 study. The liquid waste in
the site appeared in more diverse colors than in 1977.
A geological report on the fault system in the area revealed
that the Green Valley Fault tranverses the hillside less than 1,520 m
east of this facility [Figure Bl in Appendix B]. This fault is report-
edly capable of an earthquake of magnitude 6.75 with accompanying
land surface displacement. The proximity of this Class 1 site to the
geologic fault coupled with its location uphill of the city of Benicia
creates a potential hazard to the environment.
The open area immediately to the south of the U.S. Steel Corpor-
ation, Pittsburg Works, Pittsburg, California, was a large disposal
site of solid waste. This area is within the domain of the U.S. Steel
facility. The waste disposed in this area was varied in color and
volume. A brown substance was present, that according to the Cali-
fornia State Department of Health personnel, purportedly was contami-
nated with polychlorinatedbiphenyls (PCBs) in 1977. The disposal
area of this substance were much larger and more widespread than in
the 1977 survey. No dikes or other containment-structures were present
around these pits.
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There were more lined holding ponds in the wastewater treatment
facilities, southeast of the U.S. Steel Corporations main plant, during
this survey than in 1977.
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III. RESULTS OF THE INVESTIGATION
The aerial photographic data were analyzed, employing photo in-
terpretation techniques, in the NEIC Remote Sensing Laboratory. The
results of the analysis are documented herein. The geographic loca-
tions of the significant findings were plotted on the U.S. Geological
Survey (USGS) 7.5 minute charts (Topographical Maps, Scale 1:24,000).
The applicable sections of the charts are included in this report and
appropriately identified by subtitle and figure number. The alpha-
numeric symbols used to identify the specific observations on these
chart sections (printed in red), correspond to the applicable discus-
sions given below. The geographic location of each section of the
original 7.5 minute charts is depicted on the Location Map [Figure 1].
Copies of selected aerial photographs with the alpha-numeric symbols
overprinted in red, are included as an aid to more clearly depict the
observations discussed in the text. Some observations are only por-
trayed on the respective chart sections if there were no significant
changes or features.
MILPITAS CHART [Figure 2]
1 This 18-pond complex was located at the northern city boundary
of Milpitas. Two double tanker trucks were present at the time
of flight. No discharge from these trucks was visible. The ponds
contained a dark gray-brown liquid. Material dredged from the
ponds was lying in piles along the edge of several ponds [Figure 3],
There was no apparent discharge into the canal along the west
side of the ponds.
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Figure I. Location Map, San Francisco Bay Area, California
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Figure 2. Secf/on of fhe >Mi/pi/as 7.5 M/nufe Chcrrf
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Figure 3. Wasfewcrfer Ponds, Mifpifas, California
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10
OAKLAND WEST CHART [Figure 4]
2 In this small industrial facility the building and adjacent grounds
area were covered by a yellow substance [Figure 5] with the excep-
tion of the southwest corner of the plant site. The facility
had several open cylindrical tanks and a clarifier that had con-
tained a yellow liquid of an identical color to that scattered
about the grounds. The yellow substance was also covering areas
beyond the boundries of this facility.
RICHMOND CHART [Figure 6]
3 This impoundment contained a white-to-light gray-solid material
as indicated on the photograph [Figure 7]. Several ponds were
formed in low areas or depressions within the area. For the
most part, the liquid was the same color as the white material.
Some of the liquid was a light milky green.
4 This was an open or uncovered disposal site. There were yellow
and dark-brown substances disposed in piles. There were several
small ponds that contained a gray-brown liquid. The ponds were
in a depression and not lined [Figures 8, 9].
5A This area had two groups of cylindrical tanks that appeared in
poor condition [Figures 8, 9]. There were several ponds that
contained a gray-brown liquid. The ponds were in low spots.
The northern pond appeared to have resulted from extensive leak-
age from that group of tanks. There was an old rusty tank lying
in the pond. The waste liquid around the tanks and the pond was
dark gray-brown. On both sides of the rusty tank in the pond
was a light-brown liquid. The area in and around the southern
group of tanks appeared in much the same way, with the dark gray-
brown liquid around the tanks forming a pond.
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11
Figure 4. Section of the Oakland West 7.5 Minute Chart
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12
Figure 5. Ye//ow Stained Industrial Site, Emeryville, California
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Figure 6. Sect/on of the Richmond 7.5 Minute Chart
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14
Figure 7. Containment Pond, Berkeley, California
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15
Figure 8. Open Disposal Site, Richmond, California
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16
Figure 9. Liquid Waste Disposal Site, Richmond, California
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17
5B Rusty cylindrical tanks were noted west of Annotation 5A.
There were no obvious spills visible in the area [Figure 8, 9].
SAN QUENTIN AND RICHMOND CHARTS [Figure 10]
6A Two waste disposal ponds containing light blue liquid or sludge
were observed in this area. The ponds appeared to receive wastes
hauled in by vehicles. The discharge points appeared to be along
the south edge of the east pond and the southeastern edge of the
west pond next to four cylindrical horizontal tanks [Figure 11].
However, no vehicles were present at the time of flight. Dark
gray material was also present in the crescent-shaped (west) pond
along its eastern edge. The appearance of this area was poor.
Solid material such as soil and concrete chunks have been dumped
in piles at this location.
6B This was a solid waste or refuse dumping area containing black
and white material. The northern end of the area had been graded
over [Figure 11].
6C This area appeared to be for general refuse dumping as shown in
the aerial photograph [Figure 12]. The western end had been
graded over. There were ponds of water identical in color to
that observed in the drainage canal heading to Wildcat Creek.
This creek in turn leads to Castro Creek.
6D This uncovered refuse area contained low areas with standing
water as indicated in the photograph [Figure 13]. There were
two predominate solid waste piles, one was dark brown and the
other (to the east) was white.
7A This area appeared to be used for solid waste disposal and pos-
sibly for liquid waste as evidenced by standing liquid [Figure 14]
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IN ^L-5*--*- Ğ
:!3 -aJ'it,.- RICHMOND..
x-4-x-^w ~4-~ r~--j"-
^ ..I.? ~ JiU/ -' \ I
-^^LT s . ^^_\ I _
Figure 10. Sections of fhe Richmond and San Quenfin 7.5 Minute Charts
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19
Figure II. Waste Disposal Ponds, Richmond, California
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20
Figure 12. Genera' Refuse Dump, Richmond, California
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21
Figure 13. Open Refuse Disposal Site, Richmond, California
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22
Figure 14. Solid Waste Disposal Site, Contra Costa County, California
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23
and oil slicks. At the time of flight, there was one waste com-
pactor truck in the north end of this area. Access into this
area appeared to be through an automobile salvage yard. One
area adjacent to the auto salvage yard had been graded to a low
spot which contained a medium-grey liquid [Figure 14].
7B As indicated in Figure 10, two dredged canals were on the east
and west side of the automobile salvage yard. The canal on the
west side led into Wildcat Creek. The color of the water in
both canals was identical to that in the holding lagoon on the
south side of the salvage yard. The aerial photograph does not
indicate any physical hydraulic connection between the two canals
[Figure 15].
8 This was a solid refuse disposal area. Some of the solid material
may have been pieces of concrete. The access road is indicated
on the chart [Figure 10].
9A These two adjacent ponds contained a dark yellow-brown liquid
waste substance. An overflow from the top of a white tank had a
stain of the same color [Figure 16].
9B This pond contained an oil sludge and the water surface was covered
with numerous oil slicks [Figure 17].
9C This partially filled pond had contained a white liquid which
appeared to have evaporated, leaving a white residue. There was
no other section of this facility that had a similar color
[Figure 17].
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24
TRASH COMPACTOR
TRUCK
Figure 15. Wafer Canal Segments,
Richmond and Contra Costa County, California
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25
EPA-NEIC
Figure 16. Liquid Waste Ho/ding Ponds, Richmond, California
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Figure 17. Oil Sludge Holding Pond, Richmond, California
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PORT CHICAGO CHART [Figure 18]
10 In the 1977 study, this area was being graded down from the natural
contour as shown on the map. The 1979 study revealed this area
was now level and contained a triangular-shaped pond half full
of a jade-green liquid. There was a medium-gray discoloration
in the soil in contrast to the natural clay-colored soils on the
west side of the graded area [Figure 19].
11 A complex of ponds full of a dark-gray liquid was present at the
Vine Hill Disposal Site reportedly operated by Industrial Tank
Environmental Corporation. The denuded area indicated on the
photograph [Figure 20] contained liquid of the same color as the
ponds to the west. The liquid had moved northeast to a depressed
area, and was standing in a natural pond state as sketched on
the chart. This liquid may have seeped from these ponds due to
the presence of the Avon Segment of the Concord Fault (geological
fault) that traverses southeast to northwest through this immediate
area [Appendix A].
The U.S. Geological Survey has published a map (Miscellaneous
Field Studies Map, MF 505, scale of 1:24000) outlining the Con-
cord Fault and specifically the Avon Segment that traverses through
the above-mentioned area. A portion of this map and text excerpts
are included in Appendix A.
The west ponds were surrounded with numerous small buildings and
tanks [Figure 18].
12A This area was identified as the ACME Landfill by the State of
California. It was an active landfill in 1977 and is now closed
and completely covered with soil. There were indications of
vegetation growth over this area [Figure 18].
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Figure J8. Section of the Port Chicago 7.5 Minute Chart
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29
Figure 19. Waste Liquid Pond, Vine Hi" Area, California
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30
EPA-NEIC
Figure 20. Vine Hill Disposal Site, Martinez, California
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31
12B This area was being used as an active sanitary landfill.
ISA This pond complex (Class 1 Disposal Site) was identified as the
Baker Site by the State of California, Regional Water Quality
Control Board. It is operated by the Industrial Tank Environ-
mental Corporation and Industrial Tank Oil Corporation. A medium-
gray liquid was present in the canal along the northern and east-
ern containment dikes of this holding pond complex. The ponds
contained nearly the same color liquid with the addition of some
oil slicks. Liquid was standing in depressions between the eastern
portion of the canal and Pacheco Creek [Figure 18]. The canal
feature was not present and the area outside of the ponds was
dry in the 1977 imagery.
As shown in Appendix A, the Avon Segment of the Concord Fault
passes under the northern-most group of four ponds (Pond A) of
the Baker Site. According to Sub Chapter 15 of the State of
California Waste Disposal Regulation (Article 2, Paragraph 2510.g.),
a Class 1 site shall not be located over a fault zone.
13B This group of four ponds identified as Pond A within the Baker
Site, had a yellow or straw-colored substance floating on the
surfaces as indicated in red. This substance appeared to be an
adsorptive material.
13C The color of these ponds, Ponds B, C, D, and E within the Baker
Site, were medium-gray, whereas in 1977 they were dark-gray to
nearly black. The long narrow ponds as indicated on the chart,
between Ponds A, B, and C also contained a gray liquid. In 1977
there were no long narrow ponds at these locations.
13D This solid waste disposal site appeared to be more heavily used
than in 1977.
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32
14 This automobile salvage yard is somewhat larger in surface area
than was recorded in 1977.
BENICIA AND PORT CHICAGO CHARTS [Figure 21]
15 The Industrial Tank Environmental Corporation (formerly The Pacific
Reclamation and Disposal Company) facility had been enlarged since
1977. There were approximately 10 additional ponds bringing the
pond complex total to at least 54. Figures 22, 23, and 24 provide
an overview of the pond complex. This is a Class 1 disposal
site.
A greater variety of color of the liquid waste was observed during
this study than present in 1977. This may in part be due to the
fact that the 1977 and 1979 aerial surveys were conducted in
different seasons, summer and spring respectively. The color
ranged from light brown through rust to dark-gray (charcoal) and
gray-green in the 1979 survey.
ISA Tanker trucks were in the facility at the time of the aerial
surveillance [Figures 25, 26,27].
15B This pond was formed by an earthen dam across a small valley and
contained a liquid that was light green [Figure 28]. There were
three separate erosion washes leading from the upper roads down-
hill into the pond. One erosion wash originated from a concrete
structure.
15C An earthen dam formed this pond that contained a medium-gray
liquid [Figure 29]. There were two erosion washes leading from
the upper road into the pond. A section of the lower road around
the rear of the pond was flooded. The dam displayed two areas
of possible liquid seepage [Figure 29].
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Figure 21. Sections of the Benicia and Porf Chicago 7.5 Minufe Charf
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34
EPA-NEIC
SUISUN BAY
Figure 22. Industrial Tank Environmental Corporation,
Benicia Disposal Site, Benicia, California,
View from North to South
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35
Figure 23. Industrial Tank Environmenfaf Corporation,
Benicia Disposal Site, Benicia, California,
View from Northwest to Southeast
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36
Figure 24. Industrial Tank Environmental Corporation,
Benicia Disposal Site, Benicia, California,
View from North Northwest to South Southeast
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37
Figure 25. Industrial Tank Environmental Corporation,
Benicia Disposal Site, Benicia, California,
View from Southwest to Northeast
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38
Figure 26. Industrial Tank Environmental Corporation,
Benicia Disposal Site, Benicia, California,
View from West to East
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39
Figure 27. Industrial Tank Environmental Corporation,
Benicia Disposal Site, Benicia, California,
View from West Southwest to East Northeast
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40
Figure 28. Industrial Tank Environmental Corporation,
Benicia Disposal Site, Benicia, California,
View from North Northwest to South Southeast
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41
POSSIBII LOWER DAM SEEPAGE
Figure 29. Industrial Tank Environmental Corporation,
Benicia Disposal Site, Benicia, California,
View from Southwest to Northeast, Southern End of the Site
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42
15D This area was graded and the two dams formed to serve as two
liquid waste disposal ponds [Figures 30, 31], with the lower
pond being the largest. In 1977 dark-brown liquid with a white
foam was present in the upper and lower level ponds. During
this study, both ponds were nearly full of liquid waste. A small
third pond had been added near the edge of the upper dam [Figure 32].
The lower dam showed many more indications of seepage and/ or
overspills of the dark liquid waste than was present in 1977. A
tanker truck was discharging into the lower pond at the time of
flight.
Geologic reports on the Northern California earthquake fault
system indicate that the Green Valley Fault traverses north-north-
west less than 1520 m (1660 yards) east of the Industrial Tank
Environmental Corporation's Pond complex. The information is
published by the U.S. Geological Survey as Miscellaneous Field
Studies Map MF 743. A portion of this map and text excerpts are
provided in Appendix B.
Although this Class-1 disposal site is not located directly over
the fault zone [Annotation 13A] it could possibly pose a hazard
to the structural integrity of the site. The potential of an
earthquake of magnitude 6.75 with accompanying ground surface
displacement (about 1 m) is possible in the area.
16 The wastewater treatment plant (WWTP) purportedly operated by
the Exxon refinery in Benicia, contained four holding ponds. A
large diameter white pipe led from the refinery to the WWTP.
The wastewater from the pipe proceeded through a concrete struc-
ture and an open flume into the treatment facility [Figures 33,
34]. Wastewater was being discharged into the third pond from
the north accompanied by a buildup of white foam. There was a
manifold discharge into the southern most rectangular pond. A
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43
EPA-NEIC
15D
\
t
\
Figure 30. Industrial Tank Environmental Corporation,
Benicia Disposal Site, Benicia, California,
View from West Southwest to East Northeast, Middle Area
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44
Figure 37. Industrial Tank Environmental Corporation,
Benicia Disposal Site, Benicia, California,
View from North to South, Middle Area
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45
EPA-NEIC
Figure 32. Industrial Tank Environmental Corporation,
Benicia Disposal Site, Benicia, California,
View from North Northeast to South Southwest, Northern Area
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46
Figure 33. Exxon Refinery Wasfewafer Treatment Plant,
Benicia, California, Norfhwesf Section
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47
MANIFOLD DISCHARGE
Figure 34. Exxon Refinery Wastewater Treatment Plant,
Benicia, California, Southeast Section
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48
ditch adjacent to the northernmost pond contained wastewater
nearly identical in color to that of the largest pond, second
from the north. It appeared that a small flow of waste liquid
was being discharged into this ditch which conveyed it to a lower
flat area. At the northwest corner of the pond, there was a
stain in the soil immediately adjacent to the dike that appears
to have been caused by seepage.
ANTIOCH CHART [Figure 35]
17A This unlined pond contained a dark-brown liquid. A discharge
entered the pond at the west end. The pond was yellow-green in
this immediate area. A ditch was carrying the waste liquid to
this pond as indicated in [Figure 36].
17B One-third of the area of this pond contained a yellow-green liq-
uid. There was an outfall in the southwest corner of the pond
and a concrete structure within the embankment [Figure 37].
ISA A complex of 13 holding ponds was present in the vicinity of a
wastewater treatment plant (WWTP). Four small ponds (Arrow #1),
not artificially lined, were located immediately to the north of
the WWTP [Figures 38, 39]. Only two of the four ponds con-
tained liquid. The northeast pond was dark-gray and the southwest
pond was medium-gray. The two long, thin, rectangular concrete-
lined ponds, west of the four ponds, contained a medium-gray
1iquid.
The seven large ponds were in two groups, three on the south
side of the Atchison Topeka and Santa Fe railroad tracks that
traverse through the area, (Arrow #2), and four north of the
tracks, (Arrow #3). The northernmost pond of the group of three
contained a dark-gray liquid and the other two a medium-gray
liquid [Figure 39].
-------
Figure 35. Secfion of fhe Anh'och Nor?h 7.5 /W/nufe Charf
-------
50
EPA-NEIC
Figure 36. Liquid Waste Holding Pond,
Piffsburg Plant, Pittsburg, California
-------
51
EPA-NEIC
18E.18F
Figure 37. Liquid Wasfe Ho/ding Pond,
Adjacent to South Shore of New York Slough, Pittsburg, California
-------
52
Figure 38. Wastewater Treatment Plant, Pittsburg, California
-------
EPA-NEK
Figure 39. Holding Ponds, Wasfewafer Treafmenf Plant, Pittsburg, California
-------
54
The group of four ponds on the northside of the tracks were all
dark-gray with the exception of the non-rectangular pond which
was a dark reddish-gray. As indicated in Figures 39 and 40,
there was an indication of a spill or leak of the dark-gray liq-
uid onto the ambient soils on the west side of this group of
four ponds (Arrow #3).
18B About 900 meters (2960 ft) east southeast of the United States
Steel plant were two square, lined holding ponds [Figure 38] and
one pond in an earthen depression. The west pond had a light-gray
liquid and the other two medium-gray.
18C These two lined ponds had been constructed since the 1977 study
[Figure 38]. They contained a dark-gray liquid. The west pond
had a yellow-brown substance on the surface. No discharges
were visible.
18D An open discharge into the New York Slough from the east side of
a twin pond complex (possibly concrete lined) was observed
[Figure 40]. The east pond contained a medium-gray liquid where-
as the smaller west pond contained a gray-green liquid.
18E These two ponds contained a green-gray liquid [Figures 40, 41].
The east pond had a discharge leading to the same discharge path
as described in Annotation 18D.
18F These two areas were surface disposal sites containing yellow-gray
and medium-gray solid waste [Figures 35,40]. Surface indications
showed that the waste in the southernmost pile had been washing
into the large pond of Annotation 18E.
18G A white substance was disposed on the surface of this area
[Figures 37, 40, 41].
-------
55
EPA-NEIC
Figure 40. Large Holding Ponds,
Wasfewafer Treatment Plant, Pittsburg, California
-------
56
EPA-NEIC
Figure 41. Natural Holding Ponds,
Wasfe wafer Treatmenf Plant, Piffsburg, California
-------
57
18H A gray-brown liquid was present in this irregular shaped pond
['Figure 35]. There appeared to be a an outlet along the east
side of the pond to a canal as indicated on the chart.
181 This elongated unlined pond, in an earthen depression, contained
a gray-green liquid. There was a large horizontal cylindrical
tank at the north end. A possible pair of pipes was observed
lying over the southwestern embankment [Figures 38, 39].
JERSEY ISLAND CHART [Figure 42]
19 The appearance of these ponds containing a light gray-green liquid
had not changed substantially from the 1977 report.
HONKER BAY AND ANTIOCH NORTH CHARTS [Figure 43]
20A These five ponds appeared to have no artificial lining and con-
tained a yellow-brown liquid. They were located along the west
side of the United States Steel Company, Pittsburg Works, facility.
The bottom of the center pond was not completely covered with
the liquid [Figure 44]. The ponds contained no liquid in the
1977 coverage.
20B This pond appeared to have no artificial lining, and it contained
a yellow-brown liquid. It had been added since the 1977 coverage
[Figure 44].
20C Beside the railroad spur was a small unlined pond containing a
dark-gray liquid. The 1977 coverage indicated the area was dry
and the soil was a gray-brown [Figure 44].
-------
Figure 42. Section of fhe Jersey Island 7.5 Minute Chart
-------
Figure 43. Sections of fhe Honker Bay and Antioch North Charts
-------
60
Figure 44. Waste Disposal Site, U.S. Steel Corporation,
Pittsburg Works, Pittsburg, California
-------
61
20D Several piles of a gray solid substance were present during this
and the 1977 coverage [Figure 44].
20E A long thin pile of solid waste or refuse was located here. It
was not present during the 1977 study [Figure 44].
21 Three piles of a medium gray-brown solid substance were present
here [Figure 45]. There was an open ditch leading from a white
building to New York Slough.
22 This large dark-gray pile of solid material along the shoreline,
did not appear to be washing into the New York Slough. It was
being moved and maintained by grading equipment. It may have
been a coal or coke stockpile [Figure 45].
23 These three small ponds contained a gray-green liquid. The western-
most pond was supplied by an open ditch as indicated in Figure 46.
A small pond or area just to the east contained a yellow-brown
substance.
24 The following observations were located within the open or un-
covered disposal site at the U.S. Steel Corporation's Pittsburg
Works.
24A These four areas containing a medium-brown solid substance were
also present in 1977. At that time, California State Health
Personnel indicated the substance was contaminated with poly-
chlorinated-biphenyls (PCB's). These areas are much larger than
in 1977. There were no dikes or other containment structures
around these piles. There were indications showing that the areas
had been graded or contoured [Figures 47, 49, 50, 51].
24B These areas contained numerous piles of a medium-gray solid sub-
ance [Figures 47, 48, 49, 50, 51, 52].
-------
62
EPA-NEK
< \' ".'V1
Figure 45. Coal Storage Facility, Pittsburg, California
-------
63
Figure 46. Northern Area of the U.S. Steel Corporation,
P/ffsburg Works, Piffsburg, California
-------
64
EPA-NEIC
Figure 47. Southern Area, Open Dispose/ Site,
U.S. Steel Corpora/ion, Piffsburg Works, Piftsburg, California
-------
65
EPA-NEIC
Figure 48. Southeastern Area, Open Disposal Site,
U.S. Steel Corporation, Piffsburg Works, Piffsburg, California
-------
66
A*
Figure 49. Norfhwesfern Area, Open Disposal Site,
U.S. Steel Corporation, Pittsburg Works, Piffsburg, California
-------
67
Figure 50. Western Area, Open Disposal Site,
U.S. Sfee/ Corporation, Piffsburg Worfcs, Pittsburg, California
-------
68
Figure 51. Northern Area, Open Disposal Sife,
U.S. Steel Corporation, Pittsburg Works, Pittsburg, California
-------
69
Figure 52. Northeastern Area, Open Disposal Site,
U.S. Steel Corporation, Pittsburg Works, Pittsburg, California
-------
70
24C These areas contained numerous piles of a white solid substance
[Figures 47, 49, 50, 51].
24D This large graded area contained a mixture of a medium-gray sub-
stance and solid refuse [Figures 49, 50].
24E In addition to the predominant medium-gray solid substance, this
area contained many yellow objects which may have been barrels
or containers [Figures 49, 51].
24F A pile of a dark-gray solid substance was observed [Figures 51, 52].
24G Piles of a light-gray solid substance were present [Figure 52].
GLEN ELLEN AND PETALUMA RIVER CHARTS [Figure 53]
25A White solid waste material had been dumped into an intermittent
stream bank or wash [Figure 53]. An unimproved road, not por-
trayed on the chart, terminated at the dump site. The road ap-
peared to be in repeated use [Figures 53 and 54].
25B A disposal site for a white solid waste material was observed
2 km (1.3 miles) to the southeast of anotation 25A and about 175 m
(190 yards) behind several farm buildings. There was no defined
road or path leading to this area [Figure 55].
ASTI CHART [Figure 56]
26 This small manufacturing facility had a small unlined pond con-
taining a light-gray liquid. A small intermittent stream traversed
-------
oR.Q,'
-------
72
EPA-
Figure 54. Solid Waste Disposal Site, Petaluma Area, California
-------
73
EPA-NEIC
Figure 55. Rural Disposal Site, Pefafuma Area, California
-------
Figure 56. Section of the Asti 7.5 Minute Chart
-------
75
the area from the southwest to the northeast and emptied into the
Russian River. No discharge leading to this stream or any degrada-
tion of the surrounding vegetation was apparent.
One vertical and five horizontal cylindrical tanks were located
just north of the pond. No spill stains were noted. The lumber
yard southeast contained a small rectangular unlined pond with a
medium-blue liquid [Figure 57].
-------
76
Figure 57. Small Manufacturing Facility, Asti Area, California
-------
APPENDIX A
CONCORD FAULT
MISCELLANEOUS FIELD STUDIES
MAP MF 505
U.S. GEOLOGICAL SURVEY
DEPT. OF THE INTERIOR
Reston, Virginia
1973
R.V. Sharp
-------
A-3
APPENDIX A
CONCORD FAULT
MISCELLANEOUS FIELD STUDIES
MAP MF 505
Ongoing tectonic movement along several faults of the San Andreas
system in the region around San Francisco Bay has been well established
by many geologic and geophysical studies. This paper presents new
documentation of recent activity on the Concord fault, a strand that
lies near the northward projection of the Calveras fault zone in the
eastern part of the bay area. The Concord fault extends at least
from the north shore of Suisun Bay in Solane County to the southeast-
ernmost of Ygnacio Valley. The fault passes through the downtown
area of Concord, for which it has been named, and it trends about N.
30° W., approximately parallel to the San Andreas fault.
The most pronounced topographic expression of the Concord fault
is the linear boundary between Ygnacio Valley and the Diablo Range.
The general correspondence of the fault trace with the straight moun-
tain front resembles the relation found along the Hayward fault about
25 km to the west (Radbruch, Bonilla and others, 1966). North of
Concord, where the fault traverses chiefly a flat alluvial surface,
the trace is marked by more subtle topographic features including
sags and scarps. The topographic evidence of recent activity on the
Concord fault is concentrated mainly in the area between downtown
Concord and Suisun Bay, but young fault topography also extends a few
kilometers southeast of Concord along the west side of the Lime Ridge.
Beyond the segments where evidence of young movement is clear, the
probable position of the fault trace has been inferred by analogy to
the relation of topography and faulting where recent offset is evident.
Very recent movement on the Concord fault has caused small right-
lateral offsets of a few centimeters at most on curbs, sidewalks,
bridges, railroad tracks, and other man-made structures. Because
much of the region traversed by the fault has been converted from
agricultural to suburban use too recently to have yet recorded offset,
most of the evidence of recent movement is found in a relatively old
part of Concord near the present downtown area where curbs and side-
walks date back to 1949. Signs of recent displacement are also found
near Avon, between 5 and 8 km northwest of downtown Concord. The
small lateral offsets that have been observed at all of the different
locations presumably reflect principally the youth of the affected
man-made features.
The geographic distribution as well as the apparent age and clar-
ity of recent movement documented along the Concord fault suggest
three contrasting sectors, termed here from north to south the Avon,
Concord, and Ygnacio Valley segments. Evidence gathered to date
-------
A-4
indicates that ground displacement by slow creep apparently has oc-
curred along at least part of the Avon segment. The Concord segment,
in contrast, may have moved intermittently at different rates in the
recent past and may have moved relatively rapidly after an earthquake
of intermediate magnitude in 1955. No evidence indicating that the
Ygnacio Valley segment has moved at the surface in recent time has
yet been found.
AVON SEGMENT
The Avon segment extends from the north shore of Suisun Bay south-
eastward to Buchanan Field (Figure A-l). Within this segment, evidence
of recent displacement has been found along two subparallel traces.
The probable main fault strand extends generally along the tidal channel
of Pacheco and Walnut creeks, and a secondary line of offset has been
found within the refinery complex of Avon.
South of Suisun Bay, evidence for right-lateral movement on the
main fault strand in the Avon segment has been found only on the Santa
Fe railroad bridge over Paceco Creek (at Maltby, strip map) and on
the Waterfront Road bridge over the same channel west of Avon. Measure-
ment of the displacement on the railroad bridge (abutment dated 1965)
is difficult because of the marked curvature of the structure produced
by the offset; however, the amount of lateral movement probably exceeds
5 cm. The bridge over the Paceco Creek channel along Waterfront Road
is also slightly offset, but the zone of tectonic bending probably
includes the west abutment. Linear features are lacking at the abut-
ment, so that the combined offset within the bridge and abutment is
unknown.
The fault at Avon displaces three railroad sidings and at least
four concrete structures in the refinery between 3 and 7 cm right
laterally. Although a concrete culvert beneath the sidings at the
position of the offset is dated 1913 and the sidings have existed
since 1916 (M. Morris, Southern Pacific Co., oral commun., 1973) the
displacement of the tracks may have occurred within a small fraction
of the time since then.
North of Suisun Bay, evidence of lateral ground movement has
been found only at one locality on the northern set of two Southern
Pacific railroad tracks. Although this offset lies virtually on-line
with the projected trace of the Concord fault from south of Suisun
Bay, it conceivably could have resulted from movement on an unknown
fault of different orientation. Because the track closer to the
bay is not offset, the extrapolation of the Concord fault north of
Suisun Bay along the indicated trace should be regarded as tentative.
The trace as shown is consistent, however, with the pattern of faulting
indicated by geological relations in the hills farther northwest.
-------
A-5
EPA-NEIC added the
red overlay for definition
of the relationship
between the waste
disposal sites and
the fault.
INDUSTRIAL YAK
VINE HULL SITU
K UASTH
0DSPOSAL SITU
r-\ wppfi
r-\ \S\JpBsj
\ Ğs \\Ğl ğ.' \
% Ğ* \\ o\\ 4,'-N.'0
i -A f! XV'MC \3
i
*
Figure AI
Segment of USGS 7.5 Minute Map MF 505
Avon Segment of the Concord Fault
-------
A-6
Between the warped railroad bridge at Maltby and Buchanan Field,
only one man-made feature, State Highway 4, crosses the Concord fault
as a continuous linear element. The highway is not edged with curbs,
so that detection of lateral off-set would be difficult without compar-
ison to early survey of the highway alinement. However, the alinement
of the linear scarplike slope bordering the Walnut Creek channel on
the east between Maltby and Highway 4 suggests that the fault trace
probably passes close to or beneath the Highway 4 bridge over Walnut
Creek. Although the bridge shows no obvious signs of tectonic bending,
it may have rotated slightly as a unit to accommodate right-lateral
movement in the underlying ground. Because suitable reference lines
beyond the ends of the bridge do not exist, however, rotation of the
structure cannot be demonstrated.
The relatively old runways and taxiways along the east side of
Buchanan Field show no indication of fault movement along the south-
west bank of Walnut Creek. This lack of deformation increases the
probability that the trace passes beneath the Highway 4 bridge.
Comparison of earthquake epicenters since the mid-19301s with
the alinement of the Avon segment suggests that movement is probably
occurring by the mechanism of slow creep. Recent earthquakes recorded
in the immediate area have been small (see, for example, Lee and others,
1972, fig. 4), and none of the observed offsets has an obvious associa-
tion with any specific seismic event.
CONCORD SEGMENT
The most abundant evidence of ongoing fault displacement is found
in the Concord segment, used here to designate the interval between
Buchanan Field and the westward-flowing section of Pine Creek at the
base of Lime Ridge. This part of the fault had been recognized pre-
viously as a groundwater barrier between Clayton and Ygnacio valleys
(Bader, 1969, p. 8). The fault trace is marked intermittently by a
zone of linear sags and mostly southwest-facing scarps.
Right-lateral displacement on several relatively old sidewalks
and curbs delineates the trace of the Concord fault in the downtown
Concord area. Although seasonal shrinkage and swell age of the adobe
soil has produced a multitude of minor lateral offsets as well as
congressional and extensional effects in pavement throughout the Con-
cord area, the position, amount of offset, and the right-lateral sense
of displaced features along the trace of the Concord segment show
remarkable consistency not found elsewhere in the town. This consis-
tency and the fact that adjacent but mechanically independent curbs
-------
A-7
and sidewalks, such as those found on Ashbury Drive, show nearly iden-
tical bends as they cross the fault trace constitute the most con-
vincing evidence that the movements are tectonic in origin rather
than resulting from soil creep or related phenomena.
-------
APPENDIX B
GREEN VALLEY FAULT
MISCELLANEOUS FIELD STUDIES
MAP MF 743
U.S. GEOLOGICAL SURVEY
DEPT. OF THE INTERIOR
Menlo Park, California
1976
V.A. Frizzell, Jr.
and
R.O. Brown, Jr.
-------
B-3
INTRODUCTION
This report summarizes a study of the Green Valley fault and
documents new evidence of recent activity. The study was conducted
as part of a cooperative program between the U.S. Geological Survey
and the Department of Housing and Urban Development.
The assessment of fault activity is based on photointerpreta-
tion, fieldwork, and seismic data. The kinds of evidence that demon-
strate recent movement on the fault are systematically offset natural
features, earthquake epicenters that are alined along the fault, and
offsets in man-made features.
The map that accompanies this text is designed to inform those
concerned with land use and development of the location of faults
that have moved recently. The mapped lines designate faults along
which displacements of the ground surface have occurred in the recent
past and may occur in the future. Map users are reminded, however,
that these lines are intended primarily as guides to help locate the
fault, and that they are not necessarily shown with the precision
demanded by engineering needs. This map is not a substitute for a
site investigation.
THE GREEN VALLEY FAULT
The Green Valley fault extends at least 30 km (19 mi) northwest
from Bahia on Suisun Bay to Wooden Valley. It probably continues
northwestward beyong Wooden Valley, although definite identification
of a specific fault trace is made difficult by numerous landslide
deposits (Sims and others, 1973, Sims and Frizzell, 1976). South of
Bahia, the fault does not appear to continue directly across Suisun
Bay, but instead appears to be an echelon with the northernmost ex-
tension of the Concord fault, an active fault mapped by Sharp (1973).
The Green Valley fault was recognized early in this century by
A.C. Lawson and his coauthors, who noted that "the western edge of
the Sacramento Valley, from Benicia to Cordelia, is probably deter-
mined by a fault with an easterly downthrow." Although Tolman (1931)
called the Green Valley fault a part of the Mt. Diablo thrust, he
stated further that near Goodyear on Suisun Bay the "fault appears to
dip fairly steeply easterly and may be later than the Mt. Diablo thrus-
ting and belong to, or lie east of, the Sunol system of faulting."
Weaver (1949) considered the northern part of the Green Valley fault
a normal fault with the downthrown side of the east.
-------
B-4
More recently, several reports present data suggesting that the
southern segment of the Green Valley fault is active. Brown (1970)
shows both the north and south segments of the Green Valley fault in
his l:250,000-scale map of active faults in the San Francisco Bay
region. Sims, Fox, Bartow, and Helley (1973) indicate that the fault
is active from Bahia to 3 km (2 mi) north of Cordelia. Likewise,
Dooley (1973) gives evidence for historical movement as well as evi-
dence for both lateral and vertical movement on this past of the fault.
Additional evidence gathered by the U.S. Geological Survey is dis-
cussed below.
GEOLOGIC SETTING
Although numerous alined topographic features indicative of young
faulting are in themselves good evidence for the presence of a fault,
juxtaposition of different rock types or rocks of different ages across
a zone with young topographic features adds a great deal of substanti-
ating evidence for the presence of an active fault. The rocks along
the fault are described from south to north.
The Sonoma Volcanics of middle and later Pliocene age has been
juxtaposed against Jurassic (?) and Cretaceous sedimentary rocks along
the Green Valley fault. The Sonoma Volcanics is present on the east
side of much of the southern segment (south of 38° 15' N) of the Green
Valley fault (Sims and others, 1973). These nonmarine volcanic rocks
range in composition from olivine basalt to silicic tuff and rhyolite,
include flows, tuffs, agglomerates, and breccias, and range in age
from 5.3 to 2.9 m.y. (Mankinen, 1972). Near Bahia the volcanic rocks
dip westward into the fault.
The Jurassic(?) and Cretaceous sedimentary rocks on the west
side of the fault along much of the southern segment are an unnamed
part of the Great Valley sequence (Sims and others, 1973). This se-
quence is mostly shale and mudstone with interbeds of thin lithic
feldspathic wacke (Ojakangas, 1968, and Weaver, 1949). Locally, how-
ever, quartz-, feldspar-, and biotite-bearing sandstone predominates
(Dooley, 1973). Although the rocks are well indurated and stand in
steep gully slopes, large landslides are common in some placed (Frizzell
and others, 1974, Sims and others, 1973, and Dooley, 1973).
Also in contact with the Sonoma Volcanics near Bahia is the Domen-
gine Sandstone, a well-sorted whitish nearshore sandstone that locally
contains Eocene fossil fragments. The Domengine overlies the Jurassic(?)
and Cretaceous sedimentary rocks, and both these units have fold axes
trending N 60° W, a 30-degree divergence from the trend of the fault.
The Tehama Formation, an irregularly bedded later Pliocene volcan-
iclastic gravel, is present along part of the east side of the southern
-------
B-5
segment (Sims and others, 1973). Best seen in a small quarry on the
west side of the small hill located NE % section 25, T.4N., R.3W., it
is also present as capping deposits on the fault-bounded elongate
north-trending ridge 3 km (2 mi) southwest of Cordelia.
The Markley Sandstone Member of the Kreyenhagen Formation is
present in the elongate ridge mentioned above and also west of the
fault north of Interstate 80. This Eocene marine unit is a medium-
to coarse-grained micaceous sandstone, and except for hard boulders
it is only partially indurated. Slopes underlain by this unit dis-
play many large landslides (Frizzell and others, 1974; Sims and others,
1973).
The northern segment of the Green Valley fault (north of 38° 15'
N) traverses terrane underlain by the Sonoma Volcanics (Sims and others,
1973). Along this segment of the fault the volcanic rocks are typi-
cally flows of dacite and andesite with minor rhyolite. Ash flow
tuffs are locally interbedded with the lava flows. Although only
relatively minor landslides occur west of the northern segment, east
of this segment a landslide 3 km (2 mi) by 6 km (4 mi) is present
(Sims and others, 1973; Sims and Frizzell, 1976).
Location of Fault Features
The faults were located chiefly through the study of three sets
of aerial photographs and by field investigations of much of the fault
zone. Black and white photographs at a scale of 1:80,000 (1 cm =
0.8 cm or 1 in = 1.25 mi) taken on May 14, 1970 provide an excellent
overview and emphasize the more prominent topographic features along
the fault. Black and white aerial photographs taken on May 9, 1964
with a scale of 1:21,000 (1 cm = 210 m or 1 in = 1750 ft) provide
more detail than the l:80,000-scale photographs. However 1:13,500-
scale (1 cm = 210 m or 1 in = 1125 ft) black and white aerial photo-
graphs taken on June 20 and July 10, 1973 provide the most detail and
sharpest contrast. The plotted locations of faults were transferred
from aerial photographs to topographic maps by visual inspection and
optical projection.
The photointerpretation of fault lines along the southern seg-
ment was verified by field inspection on all of the mapped fault traces,
but because we could not gain access to some privately owned land
only part of the northern segment was similarly verified. The north-
ern 3 km (2 mi) of the fault exhibit photogeologic evidence for recent
faulting that is as compelling as anywhere on the map. Because this
part could not be field checked, however, it is shown by long dashes
instead of a solid line.
-------
B-6
Map users should consider a line on this map not as a precisely
located fault, but as guide for field location of fault-break features.
Fault features large enough to be shown by the contour lines on the
topographic map are plotted within about 30 m (100 ft) of their correct
position. However, in areas where the features are not large enough
to be shown by the contours, the mapped fault line may be mislocated
by as much as 60 m (200 ft).
Surface Features Along the Green Valley Fault
Although produced in different and complex ways, the features
common to recently active faults are developed by repeated displace-
ments along the fault, accompanied by erosion and deposition. Evidence
of recent surface faulting includes topographic discordances, contrasts
in vegetation that reflect varying ground water depth or soil differ-
ences across a fault, anomalous drainage patterns, or offset man-made
structures. Other features are scarps, trenches, saddles, sag ponds,
and elongate ridges. These features [Figure B-l] not only help define
the location of faults, but some of them also help document recent
movement.
The features here described as being created by faulting could
have been produced individually by some process other than faulting,
such as landsliding, stream erosion, deposition of terrace materials,
differential erosion along contacts, or human activities. However,
the alinement of these features along a linear tren^ and the coinci-
dental evidence for bedrock faulting indicate thay they were produced
by recent faulting.
Fault-produced topographic features are generally ephemeral.
Some, particularly those in the uplands, are susceptible to oblitera-
tion by erosion or landsliding, or they may be obscured by soil creep.
Others, such as those in the depositional areas, may be buried by
alluvium or other sediments or may be modified or destroyed by human
activities. Because these features are short-lived, their presence
indicates recent origin, and because they closely resemble features
preserved along faults with a historic record of surface rupture,
they indicate active faulting.
Long-term net horizontal or vertical displacements along a fault
result from episodic shifts (accompanied by earthquakes) amounting to
a few centimeters or a few meters, or from intervals of slow fault
creep without earthquakes, or from a combination of both. These types
of movement produce the topographic features that delineate the fault
lines shown on the map. The annotations along the mapped faults indi-
cate examples of these features. Many of the examples are cited because
they are exceptionally clear or well preserved, but such features are
generally present to some degree all along the mapped faults.
-------
EPA-NEIC added the red overlay for J;
definition of the relationship between ?.
the waste disposal site and the fault.
Figure BI
Segment of USGS 7.5 Minute Map MF 743
Green Valley Fault
-------
B-8
The southernmost prominent feature associated with the Green
Valley fault is a pair of saddles between two hills east of the fault
and the main upland on the west (Section 31, T.4N., R.2W., and Section
6, T.3N., R. 2W.). The 2.5-km-long (1.5 mi) segment of the fault
between these saddles consists of two traces. A large landslide is
also present west of the two saddles. The two hills, underlain by
the Sonoma Volcanics, may actually be large blocks that have slid
some distance into part of the low Suisun Marsh. Although the east-
ernmost trace of the fault here may no longer be tectonic, it may be
related to this large-scale downslope movement. This trace, therefore,
might act as either a fault or a landslide scarp during the next move-
ment along the Green Valley fault.
A prominent east-facing scarp is located near the boundary be-
tween Section 30, T.4N., R. 3W. and Section 25, T. 4N., R. 3W. North
of this, an elongate ridge trending N. 30° W. is located 3 km (2 mi)
south-southeast of Cordelia. This elongate ridge probably owes its
existence to the presence of subparallel strands of the Green Valley
fault immediately east and west of the ridge.
North of Green Valley the fault consists of two subparallel faults
as much as 1.6 km (1 mi) apart. These faults follow Wild Horse and
Green Valley Creeks and straddle the continuation of an unnamed ridge
between these creeks until the ridge terminates near Jenkins Rock to
the north. The northernmost 3 km (2 mi) of the western branch is
defined by well-preserved hillside benches, a linear valley and a sag
depression.
ACTIVITY OF THE FAULT
The degree of hazard posed by a fault depends in part upon the
activity of the fault. In their study on faults in Santa Cruz County,
Hall, Sarna-Wojcicki, and Dupre (1975) listed their criteria (modi-
fied after Brown, 1972) for classifying faults with a high potential
for surface rupture (a fault should meet two of the criteria to be so
classified):
a. length of at least 10 km (6 mi)
b. historic records of surface faulting and large magnitude
earthquakes
c. fault traces marked by abundant topographic features that
are geologically ephemeral (for example, sag ponds) or that
demonstrate repeated and systematic displacements (for ex-
ample, offset drainage channels)
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B-9
d. frequent small-magnitude earthquakes along or adjacent and
parallel to fault zone
e. systematic displacement of Holocene strata (deposits less
than 10,000 years old)
f. current and measurable systematic displacements across the
surface of the fault zone (fault creep or accumulation of
elastic strain)
The Green Valley fault meets five of the six criteria listed
above. The overall length of the fault is at least 30 km (19 mi).
Seismicity in the area confirms activity on the Green Valley
fault. Although epicenters should be interpreted with caution (Brabb,
1967), epicenters located using preliminary arrival data for earth-
quakes in the period 1968-74 define a zone that is nearly coincident
with the mapped fault [Figure 2]. Except for an oval zone of epicen-
ters along the Healdsburg-Rodgers Creek fault (not shown here), the
zone of epicenters along the Green Valley fault contrasts sharply
with the seismicity of the north San Francisco Bay region which is
made up of widely spaced earthquakes of magnitude 2 or less. The
epicenters along the Green Valley fault represent earthquakes of magni-
tude 2 or less. The epicenters along the Green Valley fault represent
earthquakes with magnitude of 3.9 and less. Although no focal plane
solutions are yet available, the preliminary data indicate that the
earthquakes are associated with a steeply dipping fault zone. This
is consistent with strike-slip faulting and the structural data collec-
ted in the field.
The Green Valley fault offsets units of Holocene age. In addi-
tion to apparent movement in the large landslide noted 5 km (3 mi)
north of Bahia, logs of the walls of exploratory trenches show offsets
of clay units (Dames and Moore, 1972; Burkland and Associates, 1973,
both on file U.S.G.S. Library, Menlo Park, California). One of these
trenches (Dames and Moore, 1972, trench 1) revealed an offset deposit
that contained an obsidian flake having a hydration rind date of approx-
imately 12,000 years B.P. (U.S. Geological Survey, 1973, p. 203).
As noted on the map of the southern segment, two man-made features
exhibit right-lateral offset of about one-fourth meter. Using a method
recently developed by Sharp (R.V. Sharp, oral communication, 1974),
alinement of cross members of power transmission line towers was invest-
igated. Because of the complicated geometric relation of the fault
trace to all but one transmission line, however, only the line noted
on the map was checked for alinement. Using a planetable and alidade
station under the tower located at the south end of the elongate ridge,
four readings from two separate setups were taken in both the northeast
and southwest direction. These readings yielded an observed offset
of .21 + .01 m (8.3 + .4 in.). Projection of this observed offset
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B-10
parallel to the fault yields a true right-lateral offset of .28 + .01
m (11.0 + .4 in.) as of August 13, 1974. According to a representa-
tive of the power company (J. S. Kay, Written communication, 1973),
this line was built in 1922.
The second man-made feature that has been offset is a fieldstone
fence coincident with the boundary between Sections 2 and 11, T.4N.,
R.3W., about 1.6 km (1 mi) west of Cordelia Junction. The fence is
offset by 0.25 m (10 in.) of right-lateral movement. Although the
fence is coincident with the boundary between these two sections, it
was built prior to the survey of the boundary line in 1862 (Rober
Dittmer, oral communication, 1974; Beale, 1863).
Types of Movement of the Fault
Evidence at localities where historic movement has taken place
indicate right-hand (or right-lateral) strike-slip movement, the ter-
rane on the southwest side having moved north-northwest relative to
the terrain on the opposite side. This is consistent with the sense
of movement on many other vertical dipping faults in California. In
the San Francisco Bay area, the San Andreas, Hayward, and Concord
faults (Sharp, 1973), among others exhibit this type of movement.
Although strike-slip is the predominant type of historic movement,
this may be but a part of the net slip. Evidence from trenching (Dames
and Moore, 1972; Burkland and Associates, 1973) indicates that there
also may be some west-side-up vertical component to the net slip.
POSSIBLE EFFECTS CAUSED BY SUDDEN MOVEMENT ON THE GREEN VALLEY FAULT
Although the Green Valley fault is short compared to the 1,000 km
(600 mi) San Andreas fault, and may thereby seem insignificant in its
potential to produce large earthquakes, historical data indicate that
the Green Valley fault is sufficiently long to produce moderate to
large earthquakes. Using the half-length assumed by Wentworh, Bonilla,
and Buchanan (1972, Table 2) and their empirical method of arriving
at estimated earthquake magnitude, a 30-km-long fault has an inferred
potential for producing a 6.75 magnitude earthquake with accompanying
displacement of the ground surface on the order of one meter (Bonilla
and Buchanan, a minimum magnitude with at least two other possibilities
available. If the Green Valley and Concord faults could be considered
as a single 27-km-long (17 mi) fault, an estimated 7.0-magnitude earth-
quake could take place. Likewise, although much less probable, if
the Green Valley, Concord, and Calaveras faults could all behave as a
single 96-km-long (60 mi) fault, a 7.5 magnitude earthquake is possible.
A 6.75 magnitude earthquake with accompanying sudden displacement of
the ground surface on the order of one meter on the Green Valley fault
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B-ll
could seriously disrupt human activities. (See Nichols and Buchanan-
Banks, 1974, for a discussion of seismic hazards and land-use planning).
Should such a displacement take place, four main east-west trans-
portation routes might be temporarily closed. Both State Highway 21
and Interstate 80 cross the Green Valley fault. Although a one-meter
displacement might not completely close these highways, it almost
certainly would impede full use for some time. A displacement of 1 m
certainly would temporarily close the Southern Pacific Railroad lines
that cross the fault near Cordelia and Bahia.
At least five power transmission lines cross the Green Valley
fault. In addition, many towers for these lines are located on or
very close to the fault. The inferred earthquake could generate damage
due to shaking in addition to potential damage due to displacement.
A few telephone lines and at least one gas pipeline also cross the
fault.
Sudden movement on the Green Valley fault could disrupt delivery
of water to the city of Vallejo and the Green Valley area. Not only
does one trace of the fault go through a saddle now filled with a dam
that partially confines Lake Frey, but the pipeline delivery systems
are also close to or cross the fault. In addition, the holding reser-
voir located 1.6 km (1 mi) west of Cordelia Junction straddles one
trace of the fault, and pipelines carrying water from this facility
to Vallejo cross the fault.
As can be seen from examination of the annotated map, the fault
traces appear to lie along relatively discrete lines. The apparent
confinement of the fault-related topographic features to a single
line should not be interpreted too literally, because deformation or
even displacement can take place well beyond the main fault trace.
For instance, using data limited to North American strike-slip faults,
Bonilla found that the maximum distance from the center!ine to the
outer edge of the main fault zone is 96 m (Bonilla found that the
maximum distance from the center!ine to the outer edge of the main
fault zone is 96 m (Bonilla, 1970, [Figure 3.8]). If this is accepted
for land-use purposes, a zone approximately 200 m (600 ft) when center-
ed on the mapped fault traces should be considered as zones of poten-
tial rupture, and as such should be carefully investigated before
locating sites for single-family dwellings or other structures of a
noncritical nature. More rigorous restrictions are appropriate for
such critical uses as hospitals, emergency facilities, schools, dams,
or power plants.
Within the current limits of our knowledge, ground shaking for a
magnitude 6.75 strike-slip earthquake is expected to be similar to
that associated with the 1971 San Fernando earthquake in amplitude,
frequency content, and duration (R.A. Page, written communication
1975). Such ground motion can greatly reduce the strength of earth
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B-12
materials and help precipitate various types of ground failure. For
example, if saturated, loose, granular materials such as those found
in areas of fill or interbedded in former marshland deposits are sub-
jected to acceleration and velocity values associated with 6.5 m earth-
quake, the materials could become liquefied.
Because of the relatively large amount of landsliding in the
immediate vicinity of the fault (Sims and Frizzell, 1976; Frizzell
and other, 1974; and Dooley, 1973), accelerated rates of downslope
movement of these deposits can be anticipated during a seismic event.
This is especially true should such as event occur during the wet
season when the ground is nearly saturated.
RELATION OF THE GREEN VALLEY FAULT TO OTHER FAULTS IN THE SAN FRANCISCO
BAY REGION
The San Andreas fault is an active right-lateral strike-slip
fault that extends northwest from southern California through Hollister
to Cape Mendocino. It is the master fault in -a system that includes
the Hayward, Calaveras, Concord, and Green Valley faults, among others.
The Green Valley fault is the northernmost active fault that has thus
far been directly tied via the Concord and Calaveras faults to the
divergence of the San Andreas and Calaveras faults near Hollister.
Burford and Savage (1972) believe that these subsidiary faults are
the earternmost boundaries of the San Francisco wedge of slice of the
crust of the earth, the San Andreas fault being the southwestern bound-
ary. Recognition of the northwestern extension of the Green Valley
fault is complicated by the amount of large-scale landsliding north
of the map area. However, the map of preliminary epicenters indicates
that the trend of earthquakes extends beyond the mapped trace by at
least 22 km (14 mi). Still farther to the northwest the known epicen-
ters die out, but the lack of epicenters may only be a function of
the paucity of seismographs in that area. Although there are as yet
no known connections between the Green Valley fault and active faults
to the north, J.D. Sims (oral communication, 1974) notes that active
faults with strikes similar to the Green Valley fault exist in the
area of Clear Lake, and Carter Hearn (oral communication, 1975) and
Robert Mclaughlin (oral communication, 1975) both believe that faults
with recent movement could extend as far south from the Clear Lake
area as Collayomi Valley. Possibly these faults are a continuation
of the easternmost boundary of the San Francisco wedge. Clearly,
work needs to be done to study this possibility.
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B-13
Fault Symbols
solid line: obvious photogeologic or field
evidence of recent movement shown by such
features as scarps, benches, ridges, trenches,
saddles,or sag ponds
long dashed: where position uncertain because
of erosion of fault features
short dashed: less obvious evidence, but
very likely a fault break. Avon segment of
Concord fault from Sharp, 1973
dots: inferred connections across landslides
or bodies of water
landslide: not all landslides are shown.
See Frizzell, Sims, Nil sen, and Bartow (1974)
and Sims and Frizzell (1976) for detailed
landslide map
offset stream
beheaded stream: inferred former course of
offset stream prior to capture (diversion)
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