On February 26, 2002 the Santa Clara Board of Supervisors officially adopted the County Geologic Hazards Zones (GHZ) and the revised ordinance.

The GHZs were produced by combining information from a variety of published and unpublished sources regarding the location and extent of possible faults, landslides, compressible soils, dike failure flooding, and liquefaction. The County GHZs identify areas where available information suggests specific geologic hazards may be present. In those areas, the ordinance requires that the owner/applicant submit a geologic report (prepared and signed by a Certified Engineering Geologist [CEG]) for review by the County Geologist prior to approval of certain applications for construction. 

List of Certified Engineering Geologists (PDF) - who are licensed by the State of California and have indicated their willingness to work on individual sites located in Santa Clara County.

When the Board adopted the County GHZs in 2002, the State Geologist had already released four official Seismic Hazard Zones Maps, the landslide and liquefaction zones on those maps were incorporated into the County GHZs. At that time, the Board of Supervisors also adopted a provision that the County GHZs would be revised to include California's Seismic Hazard Zones (SHZ) when ever the State Geologist released additional SHZ maps.

The following table indicates the dates of release of State maps and data, as well as the dates that the County Hazard Zones and maps were revised.

** Milpitas Quad was re-issued on 10-19-2004 with areas in Alameda County added.
*** Mountain View Quad was re-issued on 6-20-2003 with areas in Alameda County added and 10-18-2006 with areas in San Mateo County added.

NOTE: Specific portions of the LANDSLIDE and LIQUEFACTION Hazard Zones Atlas, Data and some individual map pages were revised on different dates.  The last revision occurred on October 18, 2006.

Future releases of additional State SHZ maps will be followed by revisions of the County Geologic Hazard Zones and maps that will be posted on this website.

To view maps and download data files, click on one of the following headings to go directly to the associated page:

Fault Rupture Hazard Zones

Liquefaction Hazard Zones

Landslide, Compressible Soils, and Dike Failure Flooding Hazards Zones (Combined)

Obtaining Data and Maps

Data and maps can be downloaded from this website (see the linked index map on each hazard zone page) free of charge. Copies of CDs containing the same data files and/or paper prints of the maps may be ordered from:

San Jose Blue
835 W. Julian Street
San Jose, CA
408-295-5770

- or -

FEDEX KINKOS
1712 Old Oakland Road
San Jose, CA
408-452-7777

For information about geologic hazard zones maps produced by the California Geological Survey, go to the State of California's websites at:

Earthquake Fault Zones
- and -
Seismic Hazard Zones 
(Landslide and liquefaction-prone areas)

Maps produced by the State of California may be ordered from:

BPS Reprographics
149 Second Street
San Francisco, CA 94105
415-495-8700
Attn: Jeremiah

• LAH Hazard Map
• Certified Engineering Geologists