Digital Database of Quaternary and Younger Faults


For several years, the Fault Activity Map of California (Jennings, 1994) was the basic source for fault location and fault activity data in California. DMG Bulletin 201 and the explanatory text that accompanied the Fault Activity Map provided detailed information on references used for fault location and activity.

Subsequently, the California Geological Survey—in a cooperative agreement with the U.S. Geological Survey—began preparing compilations and fault maps for the California portion of the Quaternary Fault and Fold Database of the United States (QFFD).

The QFFD contains information on faults and associated folds that are believed to be sources of M>6 earthquakes during the Quaternary (the past 1,600,000 years). These data are compiled from thousands of journal articles, maps, theses, and other documents.

The QFFD is now the best source for detailed information on faults, and is the source of basic fault data used in Probabilistic Seismic Hazards Assessment.