


U.S. DEPARTMENT OF THE INTERIOR
U.S. GEOLOGICAL SURVEY



PRELIMINARY GEOLOGIC MAP EMPHASIZING 
BEDROCK FORMATIONS IN ALAMEDA COUNTY, 
CALIFORNIA:  A DIGITAL DATABASE

By

R.W. Graymer(1), D.L. Jones(2), and E.E. Brabb(1)



Open - File Report 96-252





This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial 
standards or with the North American Stratigraphic Code.  Any use of trade, product, or firm names is for 
descriptive purposes only and does not imply endorsement by the U.S. Government.

This database, identified as "Preliminary geologic map emphasizing bedrock formations in Alameda 
County, California:  A digital database," has been approved for release and publication by the Director of 
the USGS.  Although this database has been subjected to rigorous review and is substantially complete, the 
USGS reserves the right to revise the data pursuant to further analysis and review.  Furthermore, it is 
released on condition that neither the USGS nor the United States Government may be held liable for any 
damages resulting from its authorized or unauthorized use.



1996




(1) Western Region Mapping Group, U.S. Geological Survey, 345 Middlefield Rd., M/S 975, Menlo Park, 
CA 94025
(2) Department of Geology and Geophysics, Unversity of California, Berkeley, CA 94720

Introduction

This Open-File report is a digital geologic map database.  This pamphlet serves to introduce 
and describe the digital data.  There is no paper map included in the Open-File report.  The 
report does include, however, PostScript plot files containing images of a geologic map 
sheet and an explanation sheet.  For those interested in a paper plot of information 
contained in the database or in obtaining the PostScript plot files, please see the section 
entitled "For Those Who Don't Use Digital Geologic Map Databases" below.
	This digital map database, compiled from previously open-filed U.S. Geological 
Survey reports (Graymer and others, 1994), other published and unpublished data (see 
Sources of Data in algeo.txt), and substantial new mapping by the authors in about two-
thirds of the county, represents the general distribution of rocks and geologic structures in 
Alameda County.  Together with the accompanying text file (algeo.txt), it provides current 
information on the stratigraphy and structural geology of the area covered.  The database 
delineates map units that are identified by general age and lithology following the 
stratigraphic nomenclature of the U.S. Geological Survey.  Quaternary units are almost all 
combined into an undifferentiated unit, with the exception of some artificial deposits (Qar), 
some early Holocene or late Pleistocene gravel deposits (Qt, Qoa) and a few large 
landslides (Qls).  More specific information about the units may be available in the original 
publications.  The scale of the source maps limits the spatial resolution (scale) of the 
database to 1:50,000 or smaller.  The content and character of the database, as well as three 
methods of obtaining the database, are described below. 

For Those Who Don't Use Digital Geologic Map Databases

For those interested in the geology of Alameda County who do not use an ARC/INFO 
compatible Geographic Information System (GIS), two PostScript plot files containing 
images of much of the data in the digital database have been included in the database (please 
see the section "PostScript Plot Files" below).  Those interested who have computer 
capability can access the PostScript plot files in any of the three ways described below to 
access the digital data (please see the section "Obtaining the Digital Data") including the 
Western Region Web Page (please see the section "Web Pages").  For those without 
computer capability, we have made the plot files available to an outside vendor or we can 
provide users with the PostScript plot files on digital tape that can be used by other vendors 
(please see the section "Obtaining Plots from an Outside Vendor").

Database Contents

The digital database consists of the geologic map database itself and the supporting data, 
including a fault map, base maps, map explanation, geologic description, and references.  
The digital maps, or coverages, along with their associated INFO directory have been 
converted to ARC/INFO export files.  ARC export files promote ease of data handling, and 
are usable by some Geographic Information Systems in addition to ARC/INFO (see below 
for a discussion of working with export files).  The ARC export files and the associated 
ARC/INFO coverages and directories, as well as the additional digital material included in 
the database, are described below:

The geologic map database consists of two ARC coverages, which have been converted to 
uncompressed ARC/INFO export files:


ARC/INFO		Resultant	Description of Coverage
export file		Coverage	
--------------		-----------	--------------------------------
al_um-py.e00		al_um-py/	Faults, depositional contacts, and rock unit identities

al_um-sr.e00		al_um-sr/	Fold axes, strike and dip information
	
The database directory also includes the following supporting directory, ARC coverages, 
and files:

Directory:
	info/	INFO directory containing files supporting the 
databases.  This directory is not included in the 
database release, but is created in the process of 
converting the export files into ARC coverages.

ARC Coverages, which have been converted to uncompressed ARC/INFO export files:

ARC/INFO		Resultant	Description of Coverage
export file		Coverage	
--------------		-----------	--------------------------------

al_um-flt.e00		al_um-flt/	Map of faults and fold axes in Alameda County with 
					additional database items containing fault name (if 
					any).

al_so.e00		al_so/		Index map of sources of data (see algeo.txt for the 
					corresponding list of sources of data).

al_as.e00		al_as/		Index map of Assemblages in Alameda County (see 
					algeo.txt for explanation of Assemblages).

al_quad.e00		al_quad/	Index map of quadrangles in Alameda County.
	
al_corr.e00		al_corr/	Correlation table for the units in this map database.

al_dr.e00		al_dr/		Drainage base map.
al_cu.e00		al_cu/		Cultural base map.
al_topo.e00		al_topo/	Topographic contours base map.

ASCII text files, including explanatory text, ARC/INFO key files, PostScript plot files, and 
a ARC Macro Language file for conversion of ARC export files into ARC coverages:

	algeo.txt	A text only computer file containing detailed unit descriptions and
			geological information, plus sources of data and 
			references cited.

	aldb.txt	This file.

	alkey.un	Together, these key files produce a
	alkey.ln	plottable or displayable map explanation
	alkey.mrk	and key.


	almap.ps	A PostScript  plottable file containing an image of 
			the geologic map and base maps of Alameda County  
			at a scale of 1:75,000 (Sheet 1).

	alexpl.ps	A PostScript plottable file containing an image of
			the fault map, map keys, and index maps for
			Alameda County (Sheet 2).

	import.aml	ASCII text file in ARC Macro Language to convert ARC export files 
			to ARC coverages in ARC/INFO.

Database Release Format
	
	The database was compiled in ARC/INFO, a commercial Geographic Information 
System (Environmental Systems Research Institute, Redlands, California), and is stored in 
uncompressed ARC export format (ARC/INFO version 6) in a compressed UNIX tar (tape 
archive) file.  Tar and uncompress utilities are therefore required to extract the database 
from the tar file.  These utilities are included in most UNIX systems, and can be obtained 
free of charge via the Internet from Internet Literacy's Common Internet File Formats Web 
page (http://www.matisse.net/files/formats.html).  ARC/INFO export files (files with the 
.e00 extension) can be converted into ARC/INFO coverages (see below) and can be read 
by some other Geographic Information Systems, such as MapInfo via ArcLink.  The digital 
compilation was done using version 7.0.3 of ARC/INFO with version 3.0 of the menu 
interface ALACARTE (Fitzgibbon and Wentworth, 1991, Fitzgibbon, 1991, Wentworth 
and Fitzgibbon, 1991).

Obtaining the Digital Data

The digital data can be obtained in any of three ways:

	a.  Sending a tape with request
	b.  Anonymous ftp over the Internet
	c.  From the Western Region Geologic Information Web Page.

A 20.8 MB compressed tar file of the database and related files can be obtained by sending 
a tape with request and return address to:

	Alameda County Geologic Database
	c/o Database Coordinator
	U.S. Geological Survey
	345 Middlefield Road, M/S 975
	Menlo Park, CA 94025

Do not omit any part of this address!

The compressed tar file will be returned on the tape.  The acceptable tape types are:
	1/4 inch, 150 MB cartridge tape
	2.3 or 5.0 GB, 8 mm Exabyte tape.

To obtain the tar file by ftp, log in to your UNIX system and do the following:

	cd local_directory		-go to a directory to receive the
 					tar file
	ftp wrgis.wr.usgs.gov		-make ftp connection with the 
					USGS computer WRGIS
	Name: anonymous			-use "anonymous" as your user 
					name
	Password: your name		-use your own user name as 
					password
	cd pub/geologic			-go down to the pub/geologic directory
	cd ca/of96-252			-go down to the open file directory
	type binary			-change transfer type to binary
	get al_g1.tar.Z			-copy the compressed tar file
 					across Internet to your directory
	quit				-close the ftp connection

Web Pages

The U.S. Geological Survey now supports a set of graphical pages on the World Wide 
Web.  Digital publications (including this one) can be accessed via these pages.  The 
location of the main web page for the entire U.S. Geological Survey is 
"http://www.usgs.gov".  The web page for digital publications from the Western Region 
(including this one) is "http://wrgis.wr.usgs.gov".  In addition to providing easy access to 
the entire digital database, the Western Region web page also provides simple access to the 
PostScript plot files of the map and explanation sheet containing much of the data in the 
digital database for those interested in the geology of Alameda County who do not use 
digital databases (see below).

PostScript Plot Files

The database is in ARC export format, and therefore requires use of ARC/INFO or another 
compatible GIS system to access the information contained within it.  For those interested 
in the geology of the Alameda County who don't use an ARC/INFO compatible GIS 
system we have included two PostScript plot files.  One contains a color plot of the 
geologic map database at 1:75,000 scale (Sheet 1, almap.ps).  The second contains a color 
plot of the fault map, map keys, and index maps (Sheet 2, alexpl.ps).  Because this release 
is primarily a digital database, the plot files (and plots derived therefrom) have not been 
edited to conform to U.S. Geological Survey standards.  Small units have not been labeled 
with leaders and in some instances map features or annotation overlap.  Sample plots by the 
authors have proven to be quite legible and useful, however.  These plot files are available, 
both within the complete digital database package and as seperate files, in any of the three 
ways described above, including the World Wide Web pages.  However, the plot files are 
stored in compressed UNIX tar files requiring uncompress and tar utilities to access the 
files.  These utilities are included in most UNIX systems, or can be obtained free of charge 
via the Internet from Internet Literacy's Common Internet File Formats Web page 
(http://www.matisse.net/files/formats.html).  The PostScript images are 44 inches wide by 
34 inches high, so they require a large plotter to produce paper copies at the intended scale.  
In addition, some plotters, such as those with continual paper feed from a roll, are oriented 
with the long axis in the vertical direction, so the PostScript image will have to be rotated 
90 degrees to fit entirely onto the page.  Some plotters and plotter drivers, as well as many 
graphics software packages, can perform this rotation.

Obtaining Plots from an Outside Vendor

For those interested in the geology of Alameda County who do not use computers, we have 
made the PostScript plot files available to Capitol Color (phone: (800) 700-2656 or (408) 
727-7560, FAX: (408) 727-0737).  They will provide plots of the PostScript images of the 
geologic map sheet and explaination sheet for a fee (around $25 per sheet, with discounts 
for orders of multiple copies).  We will also provide the PostScript plot files on digital tape 
for use by other vendors.  A 40.3 MB uncompressed tar file (al_p1.tar) of the PostScript 
plot files can be obtained by sending a tape with request and return address to:

	Alameda County Geology PostScript Plotfiles
	c/o Database Coordinator
	U.S. Geological Survey
	345 Middlefield Road, M/S 975
	Menlo Park, CA 94025

Do not omit any part of this address!

The compressed tar file will be returned on the tape.  The acceptable tape types are:
	1/4 inch, 150 MB cartridge tape
	2.3 or 5.0 GB, 8 mm Exabyte tape.

Make sure your vendor is capable of reading these tape types and PostScript plot files.  
Important information regarding tape file format is included in the section "PostScript Plot 
Files" above, so be certain to provide a copy of this document to your vendor.

Extracting the Database from the Tar file

If you obtained the database on tape:
	put the tape in your tape drive
	cd local_directory		-go to a directory to receive the 
					tar file
	tar xvfb /dev/rstn 20		-/dev/rstn is the tape device with
 					n an integer, this puts the tar file 
					in local_directory
	uncompress al_g1.tar.Z		-makes a 97 MB uncompressed 
					tar file al_g1.tar
	cd local_directory2		-go to the directory that will hold 
					the directory algeo (if different 
					from local_directory)
	tar xvfb {path to tar 
	file}/al_g1.tar 20		-extract the algeo directory from 
					the tar file.

If you obtained the database by anonymous ftp or from the web page:
	uncompress al_g1.tar.Z		-makes a 97 MB uncompressed 
					tar file al_g1.tar
	cd local_directory2		-go to the directory that will hold 
					the directory algeo (if different 
					from local_directory)
	tar xvfb {path to tar 
	file}/al_g1.tar 20		-extract the algeo directory from 
					the tar file.

This process will create a directory "/algeo" that contains the ARC export files and 
supporting files as described above.

Converting ARC export files

ARC export files are converted to ARC coverages using the ARC command IMPORT with 
the option COVER.  In order to ease conversion and to maintain naming conventions, we 
have included an ASCII text file in ARC Macro Language that will convert all of the export 
files in the database into coverages and create the associated INFO directory.  From the 
ARC command line type:

Arc:  &run import.aml

ARC export files can also be read by some other Geographic Information Systems.  Please 
consult your GIS documentation to see if you can use ARC export files and the procedure 
to import them.

Digital Compilation

The geologic map information was digitized from stable originals of the geologic maps at 
1:24,000 scale for newly mapped areas and 1:62,500 scale for the rest of the county.  The 
author manuscripts (ink on mylar) were scanned using a Tektronix 4991 monochrome 
scanner with a resolution of 304.8 dots per inch.  The scanned images were vectorized and 
transformed from scanner coordinates to projection coordinates with  digital tics placed by 
hand at quadrangle corners.  The scanned lines were edited interactively by hand using 
ALACARTE, color boundaries were tagged as a contact or fault as appropriate, and 
scanning artifacts visible at 1:50,000 were removed. 

Base Maps

Base Map layers were prepared from scale-stable printing negatives of the U.S. Geological 
Survey  San Francisco (1978 edition), Stockton (1989 edition), and San Jose (1978 
edition) 1:100,000 topographic maps, which have a 50 meter contour interval.  Scanned 
and vectorized images were transformed from scanner coordinates to projection coordinates 
with digital tics placed by hand at map corners.  The images were then trimmed 
interactively by hand using ALACARTE to conform to the area of the geologic coverages, 
and the four portions were combined.  Small mismatches at the boundaries caused by slight 
differences in the original scans remain in the three base map coverages.  These base map 
layers are digital images but no information other than location is attached to the lines.  The 
base maps are provided for reference only.

Faults and Landslides

This map is intended to be of general use to engineers and land-use planners.  However, its 
small scale does not provide sufficient detail for site development purposes.  In addition, 
this map does not take the place of fault-rupture hazard zones designated by the California 
State Geologist (Hart, 1988).  Similarly, the database cannot be used to identify or 
delineate most landslides in the region, because only some large landslides are shown.  For 
a more complete depiction of landslide distribution, see Nilsen and others (1979).

Spatial Resolution

Uses of this digital geologic map should not violate the spatial resolution of the data.  
Although the digital form of the data removes the constraint imposed by the scale of a paper 
map, the detail and accuracy inherent in map scale are also present in the digital data.  The 
fact that this database was edited at a scale of 1:50,000 means that higher resolution 
information is not present in the dataset.  Plotting at scales larger than 1:50,000 will not 
yield greater real detail, although it may reveal fine-scale irregularities below the intended 
resolution of the database.  Similarly, where this database is used in combination with other 
data of higher resolution, the resolution of the combined output will be limited by the lower 
resolution of these data.  Note that in contrast to the geologic coverages, the base map 
layers have a resolution of 1:100,000, so significant discrepancies with the geologic 
coverages are possible.  The base map layers are provided for reference only.

Fault Information Map (al_um-flt)

This coverage contains additional information about the faults in Alameda County.  Named 
faults have been assigned a route in the route system FAULT.  A database item called 
FNAME has been added to the Route Attribute Table, and the fault name has been recorded 
there.  See below for more information about database items.  This coverage contains fault 
lines (arcs), but no contact lines (arcs) or polygon information.

Database Specifics

The map databases consist of ARC coverages and supporting INFO files, which are stored 
in a UTM (Universal Transverse Mercator) projection (Table 1).  Digital tics define a 7.5 
minute grid of latitude and longitude in the geologic coverages corresponding with 
quadrangle corners.  In the base map layers, the tics define a 7.5 minute grid, 
corresponding with quadrangle corners.

Table 1 - Map Projection
The map is stored in UTM projection

PROJECTION UTM		-Universal Transverse Mercator
UNITS METERS		-on the ground
ZONE 10			-UTM zone
PARAMETERS
END

  The content of the geologic database can be described in terms of the lines and the areas 
that compose the map.  Descriptions of the database fields use the terms explained in Table 
2.

Table 2 - Field Definition Terms

ITEM NAME	name of the database field (item)
WIDTH		maximum number of digits or characters stored
OUTPUT		output width
TYPE		B-binary integer, F-binary floating point number, 
			I-ASCII integer, C-ASCII character string
N. DEC.		number of decimal places maintained for floating 	
			point numbers


Lines - 

	The lines (arcs) are recorded as strings of vectors and are described in the arc 
attribute table (Table 3).  They define the boundaries of the map units, faults that do not 
bound units, the boundaries of open bodies of water, and the map boundaries.  These 
distinctions, including the geologic identities of the unit boundaries, are recorded in the 
LTYPE field according to the line types listed in Table 4.

Table 3 - Content of the Arc Attribute Tables

ITEM NAME	WIDTH	OUTPUT	TYPE	N. DEC	

FNODE#		4	5	B		starting node of 
						arc (from node) 
TNODE#		4	5	B		ending node of 
						arc (to node)
LPOLY#		4	5	B		polygon to the 
						left of the arc
RPOLY#		4	5	B		polygon to the 
						right of the arc
LENGTH		4	12	F	3	length of arc in 
						meters
<coverage>#	4	5	B		unique internal 
						control number
<coverage>-ID	4	5	B		unique 	
						identification 	
						number
LTYPE		35	35	C		line type (see 	
						Table 4)
SEL		1	1	I		user defined field used 
						to save a selected set
SYMB		3	3	I		user defined field used 
						to save symbol 
						assignments (such as 
						color)


Table 4 - Line Types Recorded in the LTYPE Field

contact, certain
contact, concealed
contact, approx. located
contact, inferred
fault, certain
fault, approx. located
fault, concealed
fault, concealed, queried
fault, inferred
fault, inferred, queried
s.s. fault, r.l., approx. located
s.s. fault, r.l., certain
s.s. fault, r.l., concealed
thrust fault, approx. located
thrust fault, certain
thrust fault, concealed
thrust fault, concealed, queried
tuff bed
water boundary
map boundary

The geologic linetypes are ALACARTE line types that correlate with the geologic line 
symbols in the ALACARTE line set GEOL61.LIN according to the ALACARTE lines 
lookup table (GEOL61.LUT).  Note that fault and s.s. fault, r.l. are assigned the same 
symbol in the lookup table.

Areas - 

	Map units (polygons) are described in the polygon attribute table (Table 5)  The 
identities of the map units from compilation sources are recorded in the PTYPE field by 
map label (Table 6).  Map units are described more fully in the accompanying text file 
algeo.txt.  Note that ARC/INFO coverages cannot contain both point and polygon 
information, so only coverages with polygon information (al_um-py, al_so, al_as) will 
have a polygon attribute table, and these coverages will not have a point attribute table.


Table 5 - Content of the Polygon Attribute Tables

ITEM NAME	WIDTH	OUTPUT	TYPE	N. DEC	
	
AREA		4	12	F	3	area of polygon 	
						in square meters
PERIMETER	4	12	F	3	length of perimeter 
						in meters
<coverage>#	4	5	B		unique internal 	
						control number
<coverage>-ID	4	5	B		unique identification 
						number
PTYPE		35	35	C		unit label
SEL		1	1	I		user defined field used 
						to save a selected set
SYMB		3	3	I		user defined field used 
						to save symbol 
						assignments (such as 
						color)


Table 6 - Map Units
(See algeo.txt for descriptions of units)


.
JKf
JKfe
JKfg
JKfgm
JKfm
JKfn
JKfs
JKgd
JKk
JKkc
JKkv
Jb
Jgb
Jpb
Jsv
Kbsh
Kc
Kcl
Kcls
Kcm
Kcu
Kcu?
Kcus
Kd
Kds
Keh
Keh?
Kel
Kjm
Kkh
Ko
Kp
Kr
Ksc
Ksh
Kslt
Kss
Ksu
Ksuh
Ksus
Ku
QTi
QTl
QTl?
Qa
Qls
Qoa
Qt
Qu
Tbd
Tbe
Tbf
Tbg
Tbgc
Tbgl
Tbi
Tbp
Tbr
Tc
Tcc
Tccs
Tcs
Tes
Tgvt
Tgvt?
Tgvtt
Th
Tlp
Tmb
Tmll
Tmls
Tn
Tnc
To
To?
Tol
Tor
Torv
Tps
Tr
Tro
Ts
Tsh
Tso?
Tsos?
Tss
Tst
Tsv
Tt
Tt?
Tte
Ttem
Ttls
Tts
Tus
Tush
Tusl
Tv
fc
fg
fl
fm
fs
gb
sc
sp
sp?



Points -

Point information (strikes and dips) is recorded as coordinate and related information and 
are described in the Point Attribute Table (Table 7).  Note that ARC/INFO coverages 
cannot contain both point and polygon information, so only coverages with point 
information (al_um-sr) will have a point attribute table, and these coverages will not have a 
polygon attribute table.

Table 7 - Content of the Point Attribute Tables

ITEM NAME	WIDTH	OUTPUT	TYPE	N.DEC

AREA		4	12	F	3	this field is not used
PERIMETER	4	12	F	3	this field is not used
<coverage>#	4	5	B		unique internal control
						number
<coverage>-ID	4	5	B		unique identification
						number
PTTYPE		35	35	C		point type (see
						Table 8).
DIP		3	3	I		dip angle in degrees
STRIKE		3	3	I		strike angle in degrees
SEL		1	1	I		user defined field used 
						to save a selected set
SYMB		3	3	I		user defined field used 
						to save symbol 
						assignments (such as 
						color)

Table 8 - Point Types Recorded in the PTTYPE Field

approx bedding
bedding
bedding w/ tops
crumpled bedding
crumpled foliation
flat bedding
foliation
foliation and bedding
joint
ot bedding
ot bedding w/ tops
vert bedding
vert bedding w/ tops
vert foliation
vert foliation and bedding
Routes - 

In the fault map coverage (al_um-flt), strands (individual arcs) of named faults are grouped 
together into routes, and fault names and related information are stored in the Route 
Attribute Table (Table 9).  The route system or subclass is named FAULT.

Table 9 - Content of the Route Attribute Tables

ITEM NAME	WIDTH	OUTPUT	TYPE	N. DEC

<subclass>#	4	5	B		unique internal 
						control number
<subclass>-ID	4	5	B		unique 
						identification number
FNAME		35	35	C		fault name

Table 10 - Fault Names Recorded in the FNAME Field

Arroyo Aguague fault
Calaveras fault
Chabot fault
Dresser fault
Greenville fault
Hayward fault
Las Positas fault
Mill Creek fault
Miller Creek fault
Mission fault
Moraga fault
Palomares fault
Pirate Creek fault
Sheridan Creek fault
South Las Positas fault
Stonybrook fault
Verona fault
Warm Springs fault
Williams fault


Acknowledgments

We are grateful to Kristin R. McDougall, William V. Sliter, David Bukry, John A. Barron, 
and William P. Elder of the U.S. Geological Survey for the paleontologic determinations 
necessary to help establish the ages of rocks in Alameda County.  Scott D. Hill, 
Superintendent of Watershed, kindly provided access to lands owned by the East Bay 
Regional Park District.  Leo T. Bauer, Alameda Division Manager, provided access to 
lands owned by the San Francisco Water Department.  G. Doug Myron, U.S. Geological 
Survey, arranged for access to some of the private land in the study area.  Carl M. 
Wentworth, Todd T. Fitzgibbon, and Geoffrey A. Phelps graciously provided assistance 
with Alacarte and ARC/INFO.  James J. Lienkaemper shared some of his knowledge of the 
creeping strand of the Hayward fault, and David. H. Oppenheimer provided maps showing 
the location of epicenters.  Larry J. Dickerson and John M. Parker, U.S. Geological 
Survey volunteers, provided extensive support in the field.  We are grateful to AmeriCorps 
for sponsoring Dickerson, Parker, and Brabb.

References Cited

Fitzgibbon, T.T., 1991, ALACARTE installation and system manual (version 1.0): U.S. 
Geological Survey, Open-File Report 91-587B.
Fitzgibbon, T.T., and Wentworth, C.M., 1991, ALACARTE user interface - AML code 
and demonstration maps (version 1.0):  U.S. Geological Survey, Open-File Report 
91-587A.
Graymer, R.W., Jones, D.L., Brabb, E.E., and Helley, E.J., 1994, Preliminary geologic 
map of the Niles 7.5-minute quadrangle, Alameda County, California:  U.S. 
Geological Survey Open-File Report 94-132, 3 sheets, 1:24,000 scale.
Hart, E.W., 1988, Fault-rupture hazard zones in California; Alquist-Priolo Special Studies 
Zones Act of 1972 with index to special studies zones maps:  California Division of 
Mines and Geology Special Publication 42.
Lienkaemper, J.J., 1992, Map of recently active traces of the Hayward fault, Alameda and 
Contra Costa Counties, California:  U.S. Geological Survey Misc. Field Studies 
Map MF-2196, 13 p., 1 sheet, 1:24,000 scale.
Nilsen, T.H., Wright, R.H., Vlasic, T.C., and Spangle, W.E., 1979, Relative slope 
stability and land-use planning in the San Francisco Bay region, California:  U.S. 
Geological Survey Professional Paper 944, 96 p.
Wentworth, C.M., and Fitzgibbon, T.T., 1991, ALACARTE user manual (version 1.0):  
U.S. Geological Survey, Open-File Report 91-587C.

