​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Welcome to the California Geological Survey

​​​​​​​THE CALIFORNIA ​GEOLOGICAL S​​URVEY is one of the oldest g​eologic​al surveys in the United State​s, having been established in 1860​. We map and analyze ​data on the state's diverse geologic environment, earthquakes, and other geologic hazards and mineral​ resources to pr​ovide critical information​ to protect life, property, commerce, and the ​​environment from natural hazards. The California Geological Survey is re​garded as the primary so​urce of geologic information used for decision-making by California's government agencies, its businesses, and the public.

–“A​LTIORA PETIMUS”​ (We Reach Higher​​)

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​CGS ​News

Date: 1/11/2018

​CGS released two new and two revised Official Alquist-Priolo Earthquake Fault Zone maps, and eight new and two revised Official Seismic Hazard Zone maps​.

​​​​​​​​​Areas covered by new and revised AP Earthquake Fault Zone maps are within Los Angeles and Napa counties, and affect the cities of Beverly Hills, Culver City, Los Angeles, Napa, Santa Monica, Vallejo, and West Hollywood. 

Areas covered by new and revised Seismic Hazard Zone maps are within Contra Costa, Riverside and San Mateo counties, and affect the cities of Antioch, Belmont, Brentwood, Burlingame, Foster City, Hillsborough, Menlo Park, Murrieta, Oakley, Redwood City, San Carlos, San Mateo, and Temecula.​​​

Date: 1/11/2018

​​​​​​​​​​​​​​​​​CGS released a major revision to its Special Publication 42 (SP 42): Earthquake Fault Zones - A Guide for Government Agencies, Property Owners / Developers, and Geoscience Practitioners for Assessing Fault Rupture Hazards in California.  SP 42 has been the primary guidance document since 1975 for providing background regarding the Alquist-Priolo Earthquake Fault Zoning Act (AP Act) and the assessment of surface fault rupture hazard.  The 2018 edition is the latest update to this document, with a focus on providing more detailed guidance to government agencies, property owners, and geoscientists who are affected by the AP Act.  This edition is freely available on the CGS website as a pdf download.​

Date: 10/19/2017

​​​​​​​​CSMIP (California Strong Motion Instrumentation Program) holds annual seminars to transfer recent research findings on strong-motion data to practicing seismic design professionals, earth scientists and earthquake response personnel as part of its Data Interpretation Project. This seminar was held on October 19th at UC Berkeley. The seminar’s program included an invited presentation on the recent damaging Mexico earthquake.​​​​

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