PSHA Map Index

Probabilistic ground shaking (Peak Ground Acceleration [PGA], 10% probability of being exceeded in 50 years, assuming a uniform soft rock site condition) contour maps have been developed for all 1 degree by 2 degree areas of California. Click below on the area desired to view the more detailed map. (Files are 5KB to 19 KB.)

Picture-image map of the California PSHA map from 1996.

1 degree by 2 degree maps:

Alturas  |  Bakersfield  |  Chico  |  Crescent City  |  Death Valley  |  El Centro  |  Eureka  |  Fresno  |  Kingman  |  Long Beach  |  Los Angeles  |  Mariposa  |  Monterey  |  Needles  |  Redding  |  Sacramento  |  Salton Sea  |  San Bernardino  |  San Diego  |  San Francisco  |  San Jose  |  San Luis Obispo  |  Santa Ana  |  Santa Maria  |  Santa Rosa  |  Susanville  |  Trona  |  Ukiah  |  Walker Lake  |  Weed


The California Department of Conservation's California Geological Survey has generated several different types of seismic hazard maps such as the one displayed above in cooperation with the U.S. Geological Survey. These maps typically indicate the probability of exceeding various levels of ground shaking during different time periods and for different soil conditions. The seismic hazard maps form the basis for building codes, mitigation strategies, loss models, and seismic hazard zones.