Most geologic maps in the San Francisco Bay area show the geology of the bedrock (the hard rocks that make up the hills and the ancient and active earthquake faults), or the Quaternary geology (young, unhardened sediments that cover the flat areas), or both.

The text-format on-line San Francisco Bay area maps can be grouped into five main topics they cover:

1. Geology of all or part of a county
2. Geology of a rectangular area (quadrangle)
3. Geology of an area of special interest
4. Geology of all of the region (may be less detailed).
5. Maps of other important geologic features (landslides, geologic materials, etc.)

Alameda County

Bedrock geologic map of Alameda County
(USGS OFR 96-252)

Quaternary geologic map of Alameda County
(USGS OFR 97-97)

Contra Costa County

Bedrock geologic map of Contra Costa County
(USGS OFR 94-622)

Quaternary geologic map of Contra Costa County
(USGS OFR 97-98)

San Mateo County

Combined geologic map of San Mateo County
(USGS OFR 98-137)

Santa Cruz County

Combined geologic map of Santa Cruz County
(USGS OFR 97-489)

Santa Clara County

Combined geologic map of Santa Clara County
(USGS OFR 97-710)

Parts of Marin, San Francisco, Alameda, Contra Costa, and Sonoma Counties

Geologic Map and Map Database of Parts of Marin, San Francisco, Alameda, Contra Costa, and Sonoma Counties, California (USGS MF 2337)  

 

Combined geologic map of the Monterey and Seaside 7.5 minute quadrangles
(USGS OFR 97-30)

Quaternary geologic map of the Napa 30 X 60 minute quadrangle
(USGS OFR 98-460)

New combined geologic map of the Palo Alto 30 x 60 minute quadrangle
(USGS MF-2332)

Combined geologic map of the Palo Alto 30 X 60 minute quadrangle
(USGS OFR 98-348)

Quaternary geologic map of the San Francisco 30 X 60 minute quadrangle
(USGS OFR 97-715)

Combined geologic map of the San Francisco South 7.5 minute quadrangle and part of the Hunters Point 7.5 minute quadrangle
(USGS OFR 98-354)

Preliminary Geologic Description of the San Jose 30 X 60 Minute quadrangle, California: A Digital Database
(USGS OFR 98-795)

Combined geologic map of the Cordelia and the northern part of the Benicia 7.5 minute quadrangles, California: A digital map database
(USGS OFR 99-162)

Bedrock geology of the Hayward fault zone
(USGS OFR 95-597)

Bedrock geology of Point Reyes National Seashore
(USGS OFR 97-456)

Quaternary geology of the Santa Clara Valley
(USGS OFR 94-231)

Geologic Map and Map Database of the Oakland Metropolitan Area, Alameda, Contra Costa, and San Francisco Counties, California (MF 2342)

Geologic Maps and Structure Sections of the southwestern Santa Clara Valley and southern Santa Cruz Mountains, Santa Clara and Santa Cruz Counties, California (MF 2373)

San Francisco Bay region landslide folio
(USGS OFR 97-745)

Elevation maps of the San Francisco Bay Region, California:
A digital database (USGS OFR 98-625)

Slope maps of the San Francisco Bay Region, California:
A digital database (USGS OFR 98-766)

Digital compilation of "Preliminary map of landslide deposits in Santa Cruz County, California, by Cooper-Clark and Associates, 1975":
A digital map database (USGS OFR 98-792)

Landslides in Alameda County, California, A Digital Database Extracted from Preliminary Photointerpretation Maps of Surficial Deposits by T.H. Nilsen in USGS Open-File Report 75-277: A Digital Map Database. (USGS OFR 99-504)

Map and Map Database of Susceptibility to Slope failure by sliding and earthflow in the Oakland area, California (MF 2385)

Seismic Landslide Hazard for the Cities of Oakland and Piedmont, California (MF 2379)

Seismic Landslide Hazard for the City of Berkeley, California (MF 2378)

For more information regarding Seismic Hazard Mapping, click here