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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)

  • 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.
  • August 15, 2016 - Effective September 6, 2016, walk-in sales services at the CGS Menlo Park Office will be discontinued. Please click here for information about ordering CGS Publications.
  • June 2, 2016 – We remember our friend and colleague Tom Montgomery Wootton who passed away on May 31, 2016.
  • February 29, 2016 – March 20-26, 2016 is Tsunami Preparedness Week. Information for emergency managers, educators, and the public is available on CGS's Tsunami information site. There's also a new poster on the effects of the March 11, 2011 Tohoku Tsunami.
  • January 26, 2016 – We remember our friend and colleague Earl William Hart who passed away in early January.
  • January 21, 2016 – The California Landslide Inventory has been updated to include new geographic areas and many smaller landslides.

Recent Releases

(expanded list of recent releases)

  • 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. 
  • November 22, 2016 - CGS Special Report ​238: Radon Potential in Western Tulare County, California. CGS has completed a radon potential study and report for western Tulare County, California. A release statement, the rep​ort​, a radon potential map, and GIS data​ are available for download.
  • September 22, 2016 - A new report on California's Non-Fuel Mineral Production in 2014 is available now. Please click here​ to read the report. 
  • 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).​​​​