SAN FRANCISCO BAY REGION 

 EARTHQUAKE PROBABILITY 



70% 



odds (10%) for one or more 

 magnitudes.? or greater 

 earthquakes from 2000 to 2030. 



This result incorporates 9% odds 

 of quakes not on shown faults. 



EXPLANATION 



21% Odds of magnitude 



6.7 or greater quakes 

 before 2030 on the 

 indicated fault 



M 



Odds for faults that were 

 not previously included 

 in probability studies 



Increasing quake odds > 



along fault segments 



Individual fault probabilities are 

 uncertain by 5 to 10% 



Expanding urban areas 



In 1999, the U.S. Geological Survey 

 and cooperators released this earthquake 

 probability map for the San Francisco Bay 

 region. The threat of earthquakes extends 

 across the entire region, and a major 

 quake is likely before 2030. As continuing 

 research reveals new information about 

 earthquakes in the bay region, these 

 probabilities are revised. 



Earthquakes, Faults, and Tectonics 15 



