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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

(archived news and events)

  • April 19, 2017 – The GeoGems--Geologic Gems of the California State Parks-- interactive web map is live and available to everyone. GeoGems Web Map
  • October 20, 2016 – Join 10+ million Californians who will Drop, Cover, and Hold On​ in The 2016 Great California ShakeOut! Learn more about earthquake safety and preparedness by clicking here.
  • October 9-15, 2016 – Earth Science Week. Learn about Earth Science Week by clicking here.
  • October 6, 2016 - California Strong Motion Instrumentation Program  (CSMIP) will hold the SMIP16 Seminar at the University of California, Irvine on Thursday, October 6, 2016. The Seminar Program and Registration Form are available at the SMIP1​6 Seminar website​.
  • August 30, 2016 – We remember our friend and colleague Jeffery Owen ​Tamb​ert who passed away on July 16, 2016.
  • August 25, 2016 - CGS sadly recognizes the recent passing of Dr. M. Lee Allison, State Geologist and Director of the Arizona Geological Survey. Click here for the Arizona Geological Society tribute to Dr. Allison.

Recent Releases

(expanded list of recent releases)

  • July 13, 2017 - Four proposed new and revised Preliminary Alquist-Priolo Earthquake Fault Zone maps.  Areas covered 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.  Click here​ for release statement. Click here​ to view or download the proposed revised maps and their associated Fault Evaluation reports.
  • June 15, 2017 -  Three Revised Official Alquist-Priolo Earthquake Fault Zone Maps.​ Areas covered are within Los Angeles County and affect the cities of Arcadia, Los Angeles, Monrovia, Pasadena, San Marino, and South Pasadena. Click here​ to view or download the Official Maps.
  • May 26, 2017 – Title II Geologic Data Compilation Project - Geology and Landslides in Selected North Coast Quadrangles of Northern California (Open File Report 79-18). Please click these links to bring up the individual pages: Forest and Watershed Geology Program Maps and GIS Data; San Francisco, San Jose and Santa Cruz; Ukiah and Santa Rosa; Weed and Redding.
  • April 13, 2017 – Updated Map Products for Alquist-Priolo Fault and Seismic Hazards Mapping Zones. The CGS Seismic Hazards Program is pleased to announce a complete revamping of all regulatory earthquake hazard zone GIS files available through the CGS Information Warehouse. A significant upgrade also has been made to PDF versions of zone maps – Alquist-Priolo fault rupture hazard zones have been combined with liquefaction and earthquake-triggered landslide zones in 7.5-minute quadrangles where multiple zone types exist. Read More...​
  • March 22, 2017 - The 2017 CGS Calendar which focuses on volcanoes and has ​photography by Mike Fuller and layout by Anita Carney is available for ​​​download. ​​
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  • ​February 1, 2017 - Geological Gems of California State Parks (SR 230) can be purchased from the CGS library. The hardcopy book includes two plates folded in a back cover pocket and costs $60.00. The two plates can be purchased separately as rolled posters and are available for $10.00 each ($20.00 for both). Free downloads of the report and plates are also available. An interactive web map is available in the GeoGems web map
  • January 26, 2017 - CGS Map Sheet 48: Earthquake Shaking Potential for California. CGS has updated the earthquake shaking potential map for California. A release statement, Map Sheet 48, and GIS data are available for download.
  • December 15, 2016 -Three revised Preliminary Alquist-Priolo Earthquake Fault Zone maps released.  Areas covered are within Los Angeles County and affect the cities of Arcadia, Los Angeles, Monrovia, Pasadena, San Marino, and South Pasadena.  Click ​​​​​h​ere for release statement. Clic​k he​re​​ to view or download the proposed revised maps and their associated Fault Evaluation reports.