San Francisco Bay Area Earthquake Loss Estimation

Note: This report has been superseded by a new probability forecast.

The USGS, the California Office of Emergency Services, the California Geological Survey, and the Association of Bay Area Governments jointly conducted a loss estimation study focused on the ten most likely damaging earthquakes forecast for the Bay Region by the Working Group. These earthquakes occur on six of the seven major fault systems in the Bay Area and range in size from a magnitude 6.7 event on a blind thrust underlying Mt. Diablo to a magnitude 7.9 repeat of the 1906 rupture on the San Andreas fault in northern California. Their 30-year probabilities range from a high of 15.2% for a M7.0 rupture of the Rodger’s Creek fault to 3.5% for a M7.4 combined rupture of the Peninsula and Santa Cruz Mountains segment of the San Andreas.

The ten most likely earthquakes and their 30-year probabilities
Ten most likely damaging Earthquake scenarios 30-year probability Magnitude
Rodgers Creek 15.2% 7.0
Northern Calaveras 12.4% 6.8
Southern Hayward (possible repeat of 1868 earthquake) 11.3% 6.7
Northern + Southern Hayward 8.5% 6.9
Mt. Diablo 7.5% 6.7
Green Valley-Concord 6.0% 6.7
San Andreas: Entire N. CA segment (possible repeat of 1906 earthquake) 4.7% 7.9
San Andreas: Peninsula segment (possible repeat of 1838 earthquake) 4.4% 7.2
Northern San Gregorio segment 3.9% 7.2
San Andreas: Peninsula + Santa Cruz segment 3.5% 7.4