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USGS Banner with Coachella Valley as seen from Keyes View in Joshua Tree National Park
Western Earth Surface Processes Team

Earthquake Hazards in Southern California

Southern Californians are well acquainted with the hazards created by earthquakes because the region is traversed by many fault zones capable of producing seismic events. Earthquake-generated hazards include:

  • Hazards due to fault rupture at the Earth's surface
  • Hazards due to ground shaking (ground acceleration)
  • Hazards due to shaking-induced ground failure (liquefaction and landslides)

A useful summary of the kinds of earthquake hazards facing southern Californians can be found in Putting Down Roots in Southern California.

Earthquake-hazard Studies by the U.S. Geological Survey (USGS)

The USGS Earthquake Hazards Program conducts research and mapping studies in southern California that answer questions about:

  • How earthquakes occur (earthquake mechanisms and sources)
  • How frequently they have occurred in the past (paleoseismology and earthquake recurrence)
  • What is the long-term slip-rate for each fault zone or segment (as a measure of long-term strain accumulation)?
  • What are the earthquake-induced hazards, where are they located, and what is their probability of occurrence?

The hazards program also conducts post-earthquake investigations that map ground-rupture patterns, evaluate ground-response patterns, and determine regional stress distribution throughout southern California prior to and after a major earthquake event. Extensive post-earthquake investigations have been conducted for the 1968 Borrego Mountain earthquake, the 1971 San Fernando earthquake, the 1979 Imperial Valley earthquake, the 1992 Landers earthquake, the 1994 Northridge earthquake, and the 1999 Hector Mine earthquake.

The USGS also maintains a National Earthquake Information Center
that distributes information about earthquakes to the lay public and to various Federal, State, and County agencies.

Southern California Earthquake Data Center
- The Data Center Page of the Southern California Earthquake Center (SCEC), a consortium of University, Federal, and State geoscience groups that conducts research on the character, origin, mechanisms, and hazards of earthquakes in southern California; the linked sites also contain information about the history of southern California earthquakes in the recent geologic past.

The SCEC Data-Center website has many useful links that describe earthquake activity and earthquake geology in southern California. Among these are:

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