Quaternary Fault and Fold Database of the United States

This database is the source for faults used in the National Seismic Hazard Maps, however, the spatial representation of the faults in the hazard maps was simplified and critical fault parameters were assigned to produce the hazard maps.

Interactive Fault Map

View interactive fault map.

This database contains information on faults and associated folds in the United States that are believed to be sources of M>6 earthquakes during the Quaternary (the past 2.6 million years). Maps of these geologic structures are linked to detailed descriptions and references.

Citation information - when using these data, please provide proper acknowledgment.

Fault Basics

offset in San Andreas fault
San Andreas fault zone, Carrizo Plains, central California. Photo by R.E. Wallace, USGS