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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)

  • 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.
  • March 22-28, 2015 - Tsunami Preparedness Week. Click here for more information about tsunami hazards and how to prepare.
  • March 10, 2015 - USGS, CGS, and SCEC announce new long-term earthquake forecast for California. Click here to go to descriptive page.
  • December 30, 2014 - CGS Map Sheet 62: Geology of Ring Mountain and Tiburon Peninsula, Marin County, California. Click here for Release Statement.
  • November 7, 2014 - CGS Map Sheet 61: Geologic Map of Part of Eastern Placer County, Northern Sierra Nevada, California. Click here for Release Statement.

Recent Releases

(expanded list of recent releases)

  • 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.
  • July 30, 2014 - CGS Special Report 234: Assessment of Post-Fire Runoff Hazards for Pre-Fire Hazard Mitigation Planning - Southern California. Click here for release statement. Click here to download the pdf.