,-
I l
• JI ,
•
I
-· J
-_J
1 J' I J
] ,;J
I -•
I ,;
I L
GEOLOGIC AND SEISMIC HAZARD INVESTIGATION
BUCHANAN OAKS OFFICE AND INDUSTRIAL PARK
Concord, California
Prepared for
DUFFEL FINANCIAL & CONSTRUCTION CO.
Concord, California
by
BURKLAND AND ASSOCIATES 333 Fairchild Drive
Mountain View, California
JUNE 1973
-
I I I
I I I I I I I 1 I
I I I
and AsSOCIATES CONSULTANTS IN ENGINEERING GEOLOGY • GEOPHYSICS ENVIRONMENTAL GEOLOGY • SOIL AND ROCK MECHANICS
333 FAIRCHILD DRIVE • (P.O. BOX 820) • MOUNTAIN VIEW, CA 94040 • (415) 969-3990
File No. K3-0105-Ml 11 June 1973
Duffel Financial & Construction Co. 1882 Diamond Boulevard - Suite 450 Concord, California 94520
Attention: Mr. Marshal De Bisschop
Subject: Buchanan Oaks Office and Industrial Park Concord, Contra Costa County, California GEOLOGIC AND SEISMIC HAZARD INVESTIGATION
Gentlemen:
As authorized by Mr. De Bisschop, we have completed an investigation and evaluation of the geologic conditions at the site of the proposed Buchanan Oaks Office and Industrial Park.
As indicated in the report, the active Concord Fault was found to cross the easterly portion of the property. The presence of this fault does not, in our opinion, preclude development of the property, but it does restrict a zone along the fault from use for office and industrial structures.
The attached report presents the data gathered during the course of our investigation, the conclusions drawn from that data, and our recommendations relating to the proposed development. The investigation was performed under the direction of Mr. Murray Levish, Engineering Geologist.
• MOUNTAIN VIEW SACRAMENTO SAN DIEGO
i •.·
]
1
l
1 1
J
I.
!· l
' 1 i 1 J
n §
i 'l
.. ..• ~
i j
-File No. K3-0105-Ml 11 June 1973
-
If there are any questions regarding the contents of this report, please contact the undersigned.
Very truly yours,
BURKLArfb 10:D ASSOCIATES .. ,..,. /,J
6f0cf/5/d_/ Phi:),.ip V. Burkland Certified Engineering Geologist 513
PP
Copies: 4 to Duffel Financial & Construction Co. l to Goetz, Hallenbeck & Goetz (Attn: Mr. Hallenbeck)
..
(ii) BURKLAND- AND ASSOClATES
..
I I -I I I I I I I I I I I I I I I _I
/
I
File No. K3-0l05-Ml 11 June 1973
If there are any questions regarding the contents of this report, please contact the undersigned.
Very truly yours,
BURKLAND AND ASSOCIATES
Philip v. Burkland Certified Engineering Geologist 513
pp
Copies: 4 to Duffel Financial & Construction Co. 1 to Goetz, Hallenbeck & Goetz (Attn: Mr. Hallenbeck)
(ii) BURKLAND AND ASSOCIATES
I I I I I I I I I I I I I I I I I I
'
File No. K3-0105-Ml 11 June 1973
TABLE OF CONTENTS
LETTER OF TRANSMITTAL
INTRODUCTION
Purpose and Scope Methods Location and Description of Site Geologic Setting
INVESTIGATION PROCEDURES AND RESULTS
Literature and Map Review Air Photo Interpretation Geologic Reconnaissance Exploration Trenching
SEISMIC HAZARDS
Primary Effects Secondary Effects
CONCLUSIONS
RECOMMENDATIONS
LIMITATIONS
SELECTED REFERENCES
LIST OF FIGURES
Figure 1 - Site Location and Active Faults Figure 2 - Fault Location by Others Figure 3 Geologic Site Plan Figures 4, 5 and 6 - Log of Test Trenches (pocket)
(iii)
Page No.
1 1 2 2
5 7 8 8
12 13
16
19
22
23
4 6
9
I I I I I I I I I I I I I I I I I I I
File No. KJ-0105-Ml 11 June 1973
INTRODUCTION
Purpose and Scope
This report presents the results of a detailed geologic
investigation at the Buchanan Oaks Office and Industrial
Park, Concord, Contra Costa County, California.
In a recent publication by the U. s. Geological Survey
(Miscellaneous Field Studies Map MF-505, Robert v. Sharp,
1973), the active Concord Fault is shown crossing the site.
The purposes of this investigation were to investigate the
possible presence of an active fault, and if found, to
evaluate its affect on the planned structures.
Methods
This investigation consisted of research and review of
relevant soils and geologic maps and reports, interpretation
of aerial photographs of the site and its environs, and
geologic mapping of exploration trenches. The investigation
of this site was done in conjunction with a similar geologic
investigation of the Cyclotron Corporation site, located at
the north end of the Industrial Park. The results of that work
are being reported separately to William F. Jones, Consulting
Engineer.
1 BURKLAND AND ASSOCIATES
I I I I I I I I I I I I I I I I I I I
File No. K3-0105-Ml 11 June 1973
Location and Description of Site
The Buchanan Oaks Office and Industrial Park consists of an
irregularly shaped triangular parcel, located beyond the
north end of the existing Stanwell Drive and Bisso Lane,
Concord, Contra Costa County, California. The Contra Costa
Flood Control Canal forms the western boundary and the Southern
Pacific Railroad right-of-way forms the easterly boundary.
The southern boundary is formed in part by the existing
Stanwell Industrial Park and in part by private undeveloped
land. The southwesterly portion of the Buchanan Oaks Park
is presently being developed, while the easterly portion is
presently vacant and undeveloped.
The undeveloped property is generally flat, covered with
grasses and weeds, and a few scattered oaks in the southeast
corner. A small pond, a water well and an abandoned farm
house area are also located in the southeastern corner of
the property. A water main crosses the property in a northerly
direction from the end of Bisso Lane.
Geologic Setting
The site is in the northern portion of the Ygnacio Valley.
The major portion of the site is underlain by Quarternary
Alluvium consisting of interbedded sands, clays, silts and
2 BURKLAND AND ASSOCIATES
I I I I I I I I I I I I I I I I I I I
File No. K3-0105-Ml 11 June 1973
gravels in varying mixtures. Bedrock occurred at a shallow
depth in the northeastern portion of the Cyclotron site at
the north end of the Industrial Park property. This bedrock
was not geologically dated but is thought to be of Tertiary
Age consisting of siltstones, claystones and poorly cemented
sandstones. These rocks may be similar to those exposed in
the refinery property to the north.
Earlier reference maps show the Concord Fault in the area
of the subject property. It was not, however, mapped as
active by the U. S. Geologica·1 Survey on their "Active
Fault Map" of 1970 (Brown), or their "Seismicity Map" of
the Greater Bay Area, open file 1972 (Lee, et al.). The
latter map does show a grouping of small earthquake epi
centers along the trend of the Concord Fault. Figure 1
shows the site in relation to the active faults mapped by
the U. s. Geological Survey in 1970 and 1972.
As can be observed from Figure 1, other Bay Area faults which
could affect the property with respect to ground shaking from
future earthquakes include the Franklin-Calaveras Fault,
approximately 4 miles to the west; the Hayward Fault, approxi
mately 14 miles distant; and the San Andreas Fault, more than
30 miles west of the property.
3 BURKLAND AND ASSOCIATES
-- - - -l(3-0105 -Ml
0
'
- --
0
FAULTS THAT ARE HISTORICALLY ACTIVE
OR THAT SHOW EVIDENCE OF
GEOLOGICALLY YOUNG SURFACE DISPLACEMENT,
SAN FRANCISCO BAY ' A PROGRESS REPORT•
. by
REGION l
OCT. 1970
ROBERT D. BROWN, JR.
'
- -
+
TO•~•P"'"""""'°"M'd' .. '"' .. '""'"w'''"'""~""'>"•' U''°'"'"~'~'"'""~"''"" .. j ........... ~
- - -
FIGVR£ N9. 1 4
... - - - - - - ~-
! I Ii "'""" .. ""-"''"""' ~"''
•
I I I I I I I I I I I I I I I I I I I
File No. K3-0105-Ml 11 June 1973
INVESTIGATION PROCEDURES AND RESULTS
Literature and Map Review
The geologic literature was reviewed regarding possible faults
located in the vicinity of the site and the width of fault
rupturing during earthquakes. A compilation of previously
mapped faults in the Concord-Ygnacio Valley area is presented
on Figure 2. As can be seen from the compilation, the geo-
logic structure in the area is highly complex. Some of the
data may also be in conflict,. that is some of the fault lines
may represent the same feature, plotted at different locations
by different authors.
The significant find from the review of the recent literature
is that none of the faults in the Ygnacio Valley area was
considered active until Sharp's 1973 publication. Poland
(Master Thesis 1935) indicated that the Concord-Riggs Canyon
Fault was active.
A review of seismicity data compiled by the U. s. Geological
Survey (open file map, Lee, et al., 1972) indicates a con-
centration of microseismic activity in the area extending
northward from Mt. Diablo to Concord.
5 BURKLAND AND ASSOCIATES
I I I I I I I I I I I I I I I I I I I
<~'r::f<c.:··"' <' :J, .. !' ' b'.';
'·
FAULT LOCATIONS 8Y OTHERS
-TOLMAN (1931)
- POLAND (1935) 6£DL061CAL SOC of SACRAMENTO f1964)
-cALIF. Div, M/Nt;S BuLc# !Bf
· - HAM 0952) . - 8RABB, SONEMAN, SW/ITEi<? ( 197!) --.SAUL ( 197!) ~SHAif!P (1973)
•
I I I I I I I I I I I I I I I I I I I
File No. K3-0105-Ml 11 June 1973
A list of references used in the investigation is presented
at the end of this report.
Air Photo Interpretation
Black and white and black and white infra-red stereo aerial
photographs of the site and its environs were studied to
determine any evidence for an active fault on the property.
The infra-red aerial photographs were flown on 30 April 1973,
at a scale of 1 inch to 1,000 feet. The other aerial photo
graphs are dated 1946 and 1948 at a scale of 1 inch to 1,000
feet, and 1952 at a scale of 1 inch to approximately 1,667 feet.
The traces of recently active faults can generally be recog
nized on aerial photographs by contrasts in vegetation and soil
types across the fault; and by topographic features such as
scarps, troughs, notches in hillsides, parallel ridges, off
set drainage channels, sag ponds, and closed depressions. A
study of the black and white aerial photographs did show
evidence of an active fault within the site, generally parallel
to the east property line. The data consisted of sag ponds,
drainage offsets, and a sharp tonal difference along a lineament*.
*Lineaments are defined as linear features on aerial photographs which indicate differences in vegetation, groundwater, soils, etc.
7 BURKLAND AND ASSOCIATES
I I I I I I I I I I I I I I I I I I I
File No. K3-0105-Ml 11 June 1973
Geologic Reconnaissance
The region was examined for evidence of recent faulting
and fault creep along the suspected Concord Fault trace.
Beginning at the canal, the fault trace was seen there as
gravels in vertical contact with bedrock. In the southern
part of the property, there is a sag pond and a low, but
distinct topographic scarp. Further south, there was evidence
in the School District Corporation yard of offset fences.
Continuing south, there are many springs, offset curbs and
topographic scarps. These features along the trend of the
fault all indicate active tectonic creep.
Exploration Trenching
Five exploration trenches were excavated and examined in May
1973. Trenches No. 4 and 5 were excavated across the Cyclotron
site at the north end of the property. The locations of the
trenches are shown on Figure 3.
The trenches were excavated with a trenching machine with a
bucket width of 24 inches to depths varying up to approximately
11 feet below the ground surface. Sidewalls of the trenches
were examined and continuously logged by our geologists prior
to loosely backfilling the trenches at the end of each day.
8 BURKLAND AND ASSOCIATES
8t.1cht7nc11
G~clc91'c S/te •
(ONCCRD FAUl . .T ZONE
•
81.Jriflaal / Asscc1'1i:.1 CONSULTANTS IN ENGIN!'CR!Ntl $£0L06Y
.Cig(Jr'1 .3
P/~11
(
, ,
-, '
, ,
a'
l:o Concord Avenue -
I I I I I I I I I ,I I I I I I I I
File No. K3-0105-Ml 11 June 1973
Geologic logs of the five trenches are presented at a.scale of
1 inch equals 5 feet on Figures 4, 5 and 6 (pocket).
As shown on the trench logs, the alluvium at the west end
of the trenches is in fault contact with weathered siltstone
and tan silty clays exposed at the .east end of the trenches.
The fault zone is characterized by a series of distinct planar
shear zones which have separated and off set materials on either
side of the shear zones. The maximum width of the fault zone
is 50 feet within the areas explored by trenching.
As indicated on Figure 3, the general trend of the fault within
the site is N30-3S°W. It appears to curve slightly to the west
between trenches 3 and 4. The fault planes vary from a steep
southwest dip at trench 2 to near-vertical at trench 3 to a
steep northeast dip at trenches 4 and 5. Relative displacement
on the fault appears to be up on the east side. Topsoil on the
east side of the fault was observed to be less than 1-1/2 feet
thick, in some locations, while on the west side it appeared to
be more than 3-1/2 feet thick. Horizontal (strike-slip) move
ment has probably occurred within the site (as evidenced by ob
served creep elsewhere on the fault), but evidence of horizontal
displacement was undetectable within the trenches. The fault
forms a groundwater barrier at this location. Free water entered
10 BURKLAND AND ASSOCIATES
I I I I I I I I I I I I I I I I I I I
File No. K3-0105-Ml 11 June 1973
the trenches at depths varying from approximately 3 - 8 feet
on the east side of the fault. West of the fault, the trenches
were dry to their total depth of 11 feet. Boring data within
the property indicate the water table is at a depth of approxi
mately 18 - 20 feet on the west side of the fault.
Fault f~atures within the trenches were not only observed by
members of our staff, but also by representatives of the
California Division of Mines and Geology.
11 BURKLAND AND ASSOCIATES
I I I I I I I I I I I I I I I I I I I
File No. K3-0105-Ml 11 June 1973
SEISMIC HAZARDS
The San Francisco Bay Area is considered seismically active
and contains a number of active faults (see Figure 1). A
seismic evaluation of a given site is dependent upon the
seismicity of the area, the location of the site in relation
to an active fault, the foundation or soil conditions, and
the nature of construction. Seismic hazards are subdivided
into primary and secondary effects.
Primary Effects: The primary effects are those generated by
differential movement across an active fault. Such movement
could result in ground rupture, in regional uplift, and/or
subsidence. Rupturing could be rapid as in a moderate to
large earthquake or it could be slow as~in tectonic creep.
In either case, rupturing of a fault trace could be detrimental
to any structures, including utilities which are located in
the ground rupturing zone. The width of such a rupture zone
is generally less than 60 feet. The 60-foot width is common
in areas of relatively soft and saturated alluvium. Widths
less than 60 feet, usually 20 feet or less, are common in bed
rock areas or where the groundwater table is deeper than 50
feet.
12 BURKLAND AND ASSOCIATES
--
I I I I I I I I I I I I I I I I I I I
File No. K3-0105-Ml 11 June 1973
In an attempt to determine the setback distance from the fault
at the site, we examined the fault exposures in the trenches
and the surrounding area to determine which side of the fault
was moving relative to the other. Based on the exposed geology,
it was determined that the east side was moving upward as all
the shearing was confined to the eastern block and minor shear-
ing was observed in the alluvium. The width of the alluvial
shear zone was less than 10 feet usually 2 to 3 feet. In the
eastern block, the width was 30 to 40 feet. Creep evidence
elsewhere on the fault (see Sharp, 1973) indicates right-lateral
(horizontal) movement of as much as 15 cm. since 1950. There
is evidence to suggest that the creep movements are related to
the October 1955 earthquake (magnitude 5.4) whose epicenter
is plotted very near to the trace of the Concord Fault. Sharp
suggests that rather than being continuous, the creep movement
may have either been initiated, or accelerated, by the 1955
earthquake, and that it may have terminated by the early 1960's.
This would account for the fact that the Contra Costa County
Water District reports no damage to their water main which
was constructed across the property in 1962.
Secondary Effects: Secondary effects of earthquakes are those
phenomena which result from the ground shaking. These effects
are not necessarily confined to the close proximity of an
13 BURKLAND AND ASSOCIATES
l I I I I I I I I I I I I I I I I I I
File No. K3-0105-Ml 11 June 1973
active fault but could be a result of an earthquake on any of
the active Bay Area faults. An evaluation of each of these
secondary effects is presented below.
Liquefaction occurs when low density, saturated, fine-grained,
granular soils are vibrated; this can be caused by shaking
which occurs during an earthquake. The saturated, fine-grained
granular soils can be temporarily turned into a heavy liquid
suspension when the relatively unstable grain to grain contact
is upset by shaking. In this "liquified" state, the soils
have little or no strength; this can result in settlement of
structures, floating of underground utilities, sand boils, etc.
Based on the results of this investigation, it is our opinion
that the potential for liquefaction is minimal at this site.
Lateral spreading generally occurs in areas of soft saturated
deep alluvium and consists of large masses of soil moving
toward open slopes. Lateral spreading may be a problem along
the banks of the Contra Costa Flood Control Canal but will
probably not affect the site itself.
The site is considered free of landslide hazards.
Lurch cracking is a type of ground rupture caused by shaking.
In general, it occurs in weak, saturated soils. There is a
possibility that minor ground lurching will occur to the east of
14 BURKLAND AND ASSOCIATES
I I I I I I I I I I I I I I I I I I I
File No. K3-0105-Ml 11 June 1973
the fault zone. The possibility of ground lurching west of
the fault is considered minimal.
Structural damage from ground shaking is caused by the trans
mission of earthquake vibrations from the ground into the
structure. The variables which determine the extent of shaking
damage are (1) the characteristics of the foundation materials,
(2) the design of the building or structure, (3) the quality of
the materials and workmanship used during construction, (4)
the magnitude and location of the earthquake, and (5) the inten
sity and duration of the shaking.
The amplitude of ground motion is usually greater in soft
soils and loose fills than in firm soil, properly compacted
fills, or solid rock. The most destructive effects of a
shock are usually seen in areas where the ground is unstable,
and structures are poorly designed and constructed. The
vibrational characteristics of the area should be considered
by the structural engineer in the design and construction of
all improvements.
15 BURKLAND AND ASSOCIATES
I I I I I I I I I I I I I I I I I I I
File No. K3-0105-Ml 11 June 1973
CONCLUSIONS
The following conclusions are based on our evaluation of
data obtained and studied during the investigation of the
site as described herein.
1. The active Concord Fault crosses the property within
the "zone" shown on Figure 3. The presence of the
fault does not, in our opinion, preclude the use of
the property for industrial building, but it does
place certain restrictions or limitations on its use
(see Recommendations).
2. The fault is a well-defined planar shear zone consist
ing of several shear planes within a zone 30 to 50
feet wide. The fault planes vary from steeply dipping
to the northeast, to near-vertical, to steeply southwest
dipping.
3. Field evidence indicates that the east side of the
fault has moved up relative to the west side. Vertical
movement appears to have been recent enough to offset
the topsoil horizon on either side of the fault. Creep
evidence elsewhere on the fault (see Sharp, 1973) indicates
right-lateral (horizontal) movement of as much as 15 cm.
since 1950.
16 BURKLAND AND ASSOCIATES
I I I I I I J I I I I I I I I I I I I
File No. K3-0105-Ml 11 June 1973
4. West of the fault zone the subsurface materials consist
of dense, relatively undisturbed alluvial soils. Ground-
water on the west side of the fault is at a depth of
approximately 20 feet. Within and east of the fault
zone, the exposed materials appear to be sheared and
locally soft. East of the fault, groundwater was found
at depths varying from 3 to 8 feet below the ground sur
face.
5. The primary seismic hazards of surface faulting and/or
tectonic creep are considered high within the fault zone.
6. Secondary seismic hazards, such as landsliding, lateral
spreading, lurch cracking and liquefaction are considered
minimal in the alluvium west of the fault. Liquefaction
may be of some minor consequence east of the fault if
saturated, low-density granular soils are encountered.
The materials observed in the trenches at this site do
not appear to be susceptible to liquefaction. Minor
lurch cracking of the ground surface for short distances
to the east of the fault may be a potential hazard because
of the shallow groundwater, the apparent structural re-
lationship of the fault blocks, and the observed shearing
in the trench excavations.
17 BURKLAND AND ASSOCIATES
I I I I I I I I I I I I I I I I I I I
File No. K3-0105-Ml 11 June 1973
7. Ground shaking at the Buchanan Oaks site can result
from earthquakes ,generated on the Concord Fault, or
from moderate to large earthquakes on other Bay Area
faults. The response characteristics are expected to
be different on the west side of the fault from those
on the east side, primarily because of the difference
in groundwater levels. Shaking on the east side is
expected to be more intensely felt than on the west
side.
8. Peak ground accelerations on the order of 0.2g to 0.3g
should be anticipated at this site from a moderate
earthquake (magnitude 5 - 6) on the Concord Fault, a
moderate to large earthquake (magnitude 6 - 7) on the
Hayward or Calaveras Faults, or a large earthquake
(magnitude 7 - 8+) on the San Andreas Fault.
18 BURKLAND AND ASSOCIATES
I I I I I I I I I I I I I I I I I I I
File No. K3-0105-Ml 11 June 1973
RECOMMENDATIONS
1. Because of the high hazard from future fault rupture
or tectonic creep, it is recommended that office or
industrial buildings not be constructed within the
fault zone shown on Figure 3.
2. Since future rupturing may not necessarily be confined
to the zone of previous movement, and since some margin
of safety seems reasonable in the circumstances, it is
recommended that permanent structures be set back some
distance from either side of· the· identified fault zone ..
Our evaluation of the exposed materials and our review
of the literature regarding ground rupturing, leads to
the conclusion that 25 feet is a reasonable distance
for setback from the west side of the fault zone. A
greater distance is recommended, however, for building
setback on the east side. It is our opinion that 60
feet is a more appropriate distance from the east side
because of the potential for lurch cracking and secondary
shearing within the eastern block. A setback of less than
60 feet may be used east of the fault, but it should only
be done with the understanding that there is added risk.
19 BURKLAND AND ASSOCIATES
I I I I I I I I I I I I I I I I I I I
File No. K3-0105-Ml 11 June 1973
The recommended setback distances at this site are
25 and 60 feet from the west and east sides of the
fault zone, respectively. If a lesser distance is
chosen for the east side, it should never be less than
25 feet, however.
3. The fault zone and the area within the setback lines
may be used for facilities related to industrial use
such as roadways, parking areas, spur tracks, or open
space. It should be anticipated that any such facilities
placed in the setback zone, and particularly within the
fault zone, will be subject to maintenance or repair in
the event of creep movements or sudden ground ruptures
along the fault.
4. It is recommended that major utility lines avoid crossing
the fault if possible. Where they must cross the fault,
consideration should be given to providing flexible
connections, and/or emergency shut-off valves.
5. The trench locations and fault zone have only been
approximately located in the field. For specific planning
of building layouts, etc., it is recommended they be lo
cated by survey methods. The backfill in the exploratory
20 BURKLAND AND ASSOCIATES
J
I J
J 1 J ]
I I I J
I I I I I I I ]
File No. K3-0105-Ml 11 June 1973
6.
7.
trenches should be recompacted since it was only
loosely dumped in the trenches after examination.
The locations and conditions of the backfilled
trenches should be considered in the design and con
struction of any foundations or related improvements
in the areas of the trenches.
Specific soil and foundation investigations are
recommended for each of the proposed building sites . once the building types and locations are chosen.
Construction and grading east of the fault may be
adversely affected by the shallow groundwater con
ditions. A qualified soil engineer should be
consulted if any development is planned in these
areas.
21 BURKLAND AND ASSOCIATES
I I I I I I I I I I I I I I I I I I I
File No. K3-0105-Ml 11 June 1973
LIMITATIONS
This investigation has been based upon surface reconnaissance,
studies of aerial photographs, review of geologic literature,
and inspection of trench excavations. No inference should be
drawn from the language of the report that the scope of the
investigation was any wider. It must be understood that
although the observed and reported conditions are considered
to be representative, local variations and geologic conditions
may exist for which this firm cannot assume responsibility.
This report was prepared upon your request for our services,
and in accordance with accepted standards of professional
practice. No warranty as to the contents of the report is
intended, and none shall be inferred from the statements or
opinions expressed. This report completes our contract re
quirements.
22 BURKLAND AND ASSOCIATES
I I I I I I I I I I I I I I I I I I I
File No. K3-0105-Ml 11 June 1973
SELECTED REFERENCES
1. Brabb, Earl E., Sonneman, H.S. and Switzer, John R., Jr., 1971, Preliminary Geologic Map of the Mt. Diablo-Byron Area: Contra Costa, Alameda, and San Joaquin Counties, California, U. s. Geological Survey Open File Map.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Brown, R. D., 1970, Faults That Are Historically Active or That Show Evidence of Geologically Young Surface Displacement, U. S. Geological Survey Open File Map.
California Department Water Resources, 1931, Economic Aspects of a Salt Water Barrier Below Confluences of Sacramento and San Joaquin, California Department Water Resources Bulletin No. 28, pp. 450.
California Division of Mines and Geology Bulletin 181, 1962.
Davis, F. F. and Goldman, H. B., 1958, Geologic Map of Contra Costa County, California Journal of Mines and Geology, Vol. 54, No. 4, Plate 5.
Geological Society of Sacramento, 1964, Annual Field Trip to the Mt. Diablo Area.
Gribaldo, Jones and Associates, 1972, Soil Investigation for The Cyclotron Corporation office/plant building, Contra Costa County, California.
Ham, C. K., 1952, Geology of Las Trampas Ridge, Berkeley Hills, California, California Division of Mines and Geology, Special Report 22.
Jennings, C. W., Burnett J. L. 1961, Geologic Map of California, San Francisco Sheet, published by the California Division of Mines and Geology.
Lawson, A. C., 1913, Areal Geology of the Concord, California Quad: San Francisco Folio, Geologic Atlas of the United States, u. s. Geological Survey.
23 BURKLAND AND ASSOCIATES
I I I I I ')
I I I I I I I I I I I I I
File No. K3-0105-Ml 11 June 1973
11. Lee, W. H.K., et al., 1972, Seismicity Map of the Greater San Francisco Bay Area, California 1969-1972, U. s. Geological Survey, Open File Reports.
12. Poland, 1935, Unpublished Master Thesis, Stanford University.
13. Rogers, Thomas, H., 1966, Geologic Map of California, San Jose Sheet, published by the California Division of Mines and Geology.
14. Saul, Richard, 1973, Geology of the Southwest Corner of the Walnut Creek Quadrangle: Unpublished Map.
15. Sharp, Robert V., 1973, Map Showing Recent Tectonic Movement on the Concord Fault, Contra Costa and Solano Counties, California, Miscellaneous Field Studies Map MP 505, Basic Data Contribution 55.
16. Wallace, R. E., 1968, Earthquake of August 14, 1966, Varto Area Eastern Turkey, Bull, Seis. Soc. of Amer., Vol. 58, No. 1, pp 1-47.
24 BURKLAND AND ASSOCIATES
OVERSIZED -DOCUMENT HAS
BEEN PULLED AND SCANNED WITH THE MAP
FILE.