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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)

  • November 10, 2015 – CGS Releases a new web map in collaboration with CalFire showing recent wildfire perimeters and deep landslide susceptibility. Click here.
  • October 11-17, 2015 – Learn about earth science and activities for Earth Science Week by clicking here.
  • October 15, 2015 – Join 10+ million Californians who will Drop, Cover, and Hold On in The 2015 Great California ShakeOut! Learn more about earthquake safety and preparedness by clicking here.
  • September 2, 2015 – California Strong Motion Instrumentation Program (CSMIP) will hold the SMIP15 Seminar at UC Davis Putah Creek Facility on Thursday October 22, 2015. The Seminar Program and the Registration Form are available at the SMIP15 Seminar website.
  • July 28, 2015 - CGS releases updated interactive web maps for the 2010 Fault Activity Map (map)(details) and 2010 Geologic Map of California (map)(details). The map services used in both maps are publicly available through ArcGIS Online.

Recent Releases

(expanded list of recent releases)

  • November 17, 2015 - CGS Special Report 227: Alluvial Fan Flooding Hazards: An Engineering Geologic Approach to Preliminary Assessment. Click here to download the pdf.
  • June 4, 2015 - Five proposed revised Preliminary Alquist-Priolo Earthquake Fault Zone maps. Areas covered are within Los Angeles, San Bernardino, Orange, and Riverside Counties. Release statement. Download maps and reports.
  • May 15, 2015 - California's Non-Fuel Mineral Production for 2013. The report is now available for download. Click here to download.
  • February 25, 2015 - Special Report 231 (Update of Mineral Land Classification for Portland Cement Concrete-Grade Aggregate in the Temescal Valley Production Area, Riverside County, California). Click here for release statement. Click here to download the report pdf. Click here for map Plate 1. Click here for map Plate 2.
  • December 23, 2014 - CGS Special Report 226: Radon Potential in San Mateo County, California. Click here for release statement. Click here to download the report pdf. Click here for map.