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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)

  • August 17, 2017 - Ten proposed new and revised Preliminary Seismic Hazard Zone maps. Areas covered 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, Temecula and Wildomar. Click here​​​ for release statement.​Click here​ to view or download the Preliminary Seismic Hazard Zone maps and their associated Evaluation Reports.​​
  • July 28, 2017 - California’s Non-Fuel Mineral Production in 2015. California ranked sixth among the states in non-fuel mineral production, accounting for approximately 4.2 % of the United States total. There were 717 active mines in the state and the t​otal market value of production was $3.6 billion. Click here to view or download the report.
  • ​​July 27, 2017 – Web Services for Alquist-Priolo Earthquake Fault and Seismic Hazard Mapping Zones.  The CGS Seismic Hazards Program has released all of its regulatory hazard zone data as web-based services. Read more​.
  • 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. ​