This dataset shows likely shaking intensity in the San Francisco Bay Area in any 50 year period from all possible faults. It is an equivalent risk to a 500 year flood event. A 10% in 50 years probability was chosen as it most closely aligns with current building standards in the California Building Code.

This dataset is not intended to be site-specific. Rather, it depicts the general risk within neighborhoods and the relative risk from community to community.

This dataset was developed in conjunction with the United States Geological Survey (USGS) and California Geological Survey (CGS) by determining Probabilistic Seismic Hazard Assessment for Peak Ground Velocity (PGV) for 52,961 points along a grid covering the entire Bay Area, at intervals of 0.05 degrees longitude and 0.05 degrees latitude. PGV was then converted to the Modified Mercalli Intensity (MMI) measure. This analysis incorporates soil conditions which affect the velocity of ground shaking.