Earthquakes and Tsunamis

Cal OES Earthquake and Tsunami Program

​Find out if your home or business is at risk to for earthquakes or tsunami's. Earthquakes can occur everywhere in California which means all Californians live with an earthquake risk. In addition to the shaking caused by earthquakes, other things can occur such as landslides, surface fault ruptures and liquefaction--all of which may cause injury or property damage. In addition, some areas within California are vulnerable to tsunami's should an earthquake occur. Take note of where you live, read the information provided at the My Hazards site, and contact your local city our county government for further details on how to be prepared where you live. Then quickly create a plan.
       
Populated counties, some with high concentrations of vulnerable populations, are exposed to substantial potential earthquake shaking hazards in southern California, the San Francisco Bay Area, Delta Region, Central Valley and along the Pacific Coast.

According to the California Geological Survey, hundreds of fault zones have been identified in the state, of which about 200 are considered potentially hazardous based on their slip rates in recent geological time (the last 10,000 years).
  • The San Andreas Fault zone lies at the juncture of two tectonic plates. The San Andreas Fault traverses the western part of the state from the Colorado basin in the southeast to the Bay Area in the north.
 
  • Located along the northern California coast, the Cascadia Subduction Zone is a source of major earthquakes in the Pacific Northwest.
More than 70 percent of California’s population resides within 30 miles of a fault where high ground shaking could occur in the next 50 years. Statewide, approximately 22 million people live in the 40 percent or higher seismic hazard zone. In 17 counties, more than 90 percent of the population lives in the 40 percent peak ground acceleration or higher seismic hazard zone. Although infrequent, major earthquakes have accounted for and continue to have the greatest potential for loss of life, injury and damage to property.

Quick Information

 
Check to see if you are near an earthquake fault.   Anyone with an Internet connection can now find out whether the house they want to buy is on one of California’s earthquake faults. The California Geological Survey (CGS) has posted its fault zone maps online for the first time. The 547 maps were previously available only in paper or CD formats.   CGS uses Google Maps’ address-matching technology to link users to the right map for a property’s location.   State law already requires home sellers to disclose to buyers whether a home is in an earthquake fault zone. Check out the maps here.. 

Additional Resources:

Federal Emergency Management Agency (FEMA) - Earthquake Information