Active fault

From Wikipedia, the free encyclopedia

An active fault is a fault which has had displacement or seismic activity during the geologically recent period. In the United States, an active fault is generally defined as a fault which displaced earth materials during the Holocene Epoch (during the last 11,000 or so years before present). Active faults are the most common sources of earthquakes and tectonic movements.

Active faults in California have been legally zoned by the State Geologist under the Alquist-Priolo Earthquake Fault Zoning Act of 1972. As of 2006, there are 547+ quadrangles zoned for Holocene-active faults.^[1] To legally qualify as an active fault, the fault must be sufficiently active and well-defined.

The national fault model of Quaternary faults is maintained by the U.S. Geological Survey, at its Central Region offices in Golden, Colorado. ^[2]

[edit] References

1. ^ http://www.consrv.ca.gov/CGS/rghm/ap/index.htm Alquist-Priolo Earthquake Fault Zones
2. ^ http://earthquake.usgs.gov/regional/qfaults/ Quaternary Fault and Fold Database of the United States