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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)

Recent Releases

(expanded list of recent releases)

  • July 14, 2016 - CGS Special Report: 232: Radon Potential in Orange County, California. CGS has completed a radon potential study and report for Orange County, California. A release statement, the report, a radon potential map, and GIS data are available for download.
  • July 14, 2016 - Interactive Radon Map of California. CGS has released an interactive web map providing radon potential information for areas of California with completed radon potential maps. Click here to go to the map. Downloadable GIS data for each study area can now be downloaded through the interactive map.
  • July 12, 2016 - Five Preliminary Geologic Maps Released. CGS has completed new geologic mapping for four 7.5 minute quadrangles and compilation of a new geologic map of a 30x60 minute quadrangle. The new maps of the Cayucos, Frazier Mountain, Irish Hill, and Morro Bay North 7.5 minute quadrangles and the Pt. Sur 30x60 minute quadrangle are now available for download from the preliminary geologic maps page.
  • June 10, 2016 - Seven New and Revised Official Alquist-Priolo Earthquake Fault Zone Maps Released. Areas covered include parts of El Dorado and San Bernardino counties. Click here to view or download the Official Maps.
  • January 29, 2016 - CGS Special Report 241: Maritime Tsunami Response Playbooks: Background Information and Guidance for Response and Hazard Mitigation Use is now available for download (4.3MB).