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Welcome to the California Geological Survey

In April 1860 the California Legislature established the Geological Survey of California that has evolved during its 150 years of service, and several name changes, into today’s modern California Geological Survey (CGS). Of course, the earliest history of CGS has its founding roots entwined with the discovery of gold in 1848.

CGS is dedicated to the fulfillment of its mission to provide scientific products and services about the state's geology, seismology and mineral resources that affect the health, safety, and business interests of the people of California.

CGS geoscientists, engineers and support staff take great pride in upholding the heritage of an organization that has a 150 year legacy of providing the highest quality of scientific and engineering products and services to the State of California.

Altiora Petimus (1860)

News & Events

  • March 22-28, 2015 - Tsunami Preparedness Week. Click here for more information about tsunami hazards and how to prepare.
  • March 10, 2015 - USGS, CGS, and SCEC announce new long-term earthquake forecast for California. Click here to go to descriptive page.
  • December 30, 2014 - CGS Map Sheet 62: Geology of Ring Mountain and Tiburon Peninsula, Marin County, California. Click here for Release Statement.
  • November 7, 2014 - CGS Map Sheet 61: Geologic Map of Part of Eastern Placer County, Northern Sierra Nevada, California. Click here for Release Statement.
  • November 6, 2014 - Two new or revised Official Alquist-Priolo Earthquake Fault Zone Maps released today.  Areas covered include parts of Los Angeles County.  This release introduces a new graphic presentation of these regulatory zone maps. Click here for Hollywood pdf. Click here for Hollywood GIS data. Click here for Azusa pdf. Click here for Azusa GIS data. Click here for Hollywood FER-253 Supplement. Click here for Azusa FER-249 Supplement.
  • October 17, 2014 - Today is National Geologic Map Day! Explore California's geology on the CGS Interactive map page. Or click here to download the page size simplified geologic map (pdf).
  • October 16, 2014 at 10:16 A.M. - Get Down! For the Great California ShakeOut! Once again, 9+ million Californians will Drop, Cover, and Hold On! Will you be one of them? Click here for more information.
  • October 12-18, 2014 - A world of activities are happening for Earth Science Week! Click here for more information.
  • August 24, 2014 - South Napa Earthquake, magnitude 6.0, 3:20 a.m. For more information, photos, and CGS field response, click here for the California Earthquake Clearinghouse.
  • August 18, 2014 - In memory of Rodger Chapman (1925-2014). Rodger established and supervised the CGS Geophysics Program, which contributed greatly to our understanding of the subsurface geology of California. Please click here for a link to Rodger's page.
  • July 22, 2014 - The CGS Library will be reopening on August 4th with new hours of operation. The new hours will be Monday through Thursday, 9:00 A.M. - 12:00 P.M. and 1:00 P.M. - 4:00 P.M.
  • June 30, 2014 - As part of the USGS multi-hazards project in the Long Valley Caldera-Mono Lake area, CGS developed several earthquake scenarios and evaluated ground shaking, surface fault rupture, liquefaction, and landslide hazards associated with these earthquake scenarios. Click here to review or download the report.
  • March 23-29, 2014 - National Tsunami Preparedness Week. Click here for more information.
  • February 25, 2014 - CGS can now accept electronic submittal of school projects. In addition, the 2013 CBC requires a “Site Data Report” be submitted. Click here to see more information about submitting school projects for CGS review.
  • February 14, 2014 - The Fault Evaluation Report for the Hollywood Quadrangle has been released. Click here to vew the report (FER-253); Plate 1; Plate 2; Plate 3.
  • January 17, 2014 - Northridge Earthquake 20th Anniversary. Click here for more information.
  • January 8, 2014 - CGS is pleased to announce the release of two proposed new and revised Preliminary Alquist-Priolo Earthquake Fault Zone maps. The areas covered are within Los Angeles County. Click here for release statement. Click here to view or download the proposed new and revised maps (Hollywood; Azusa). Click here for the Azusa Fault Evaluation Report (FER-249).
  • November 5, 2013 - CGS has partnered with the USGS and the Southern California Earthquake Center in the Working Group for California Earthquake Probabilities to produce the Uniform California Earthquake Rupture Forecast version 3, a new evaluation of the seismic shaking potential in California. The following website provides access to the UCERF3 report and background materials. Click here to view the report.
  • September 4, 2013 - CGS has partnered with the USGS Science Application for Risk Reduction (SAFRR) project to evaluate the effects of a statewide tsunami scenario generated by a magnitude 9 earthquake off Alaska. CGS will be participating with other SAFRR partners in a number of statewide workshops over the next several weeks. The following website provides access to the SAFRR project report and the inundation maps.
    Click here to view the report and maps.
  • July 1, 2013 - CGS has added SMARA Land Classification Maps to the Information Warehouse.
    Click to go directly to the Maps!
  • CGS's Information Warehouse
    CGS has developed a tool that allows you to search ALL of CGS's Regulatory, Landslide, Tsunami and SMARA maps using one interface.
    Begin exploring for maps!
  • Recent passing of former State Geologist Wesley G. Bruer, 1926-2013
  • A New Way to Access CGS Natural Hazard Information
    A collaborative web service called MyPlan has been established by the California Emergency Management Agency and the California Natural Resources Agency (CNRA) to provide a “one-stop shop” for local agency access to inter-active map information regarding natural hazards in California at CGS will continue to provide natural hazard information through its own website in addition to the new service.

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