The "Big One" is long overdue in Southern California

(Credit: Image courtesy of University of Oregon)

A major seismological event is long overdue for the southern end of the San Andreas Fault, but that doesn't mean it is imminent.

ScienceDaily (Feb. 10, 2011) — A chronology of 1,000 years of earthquakes at the southern end of the San Andreas Fault nixes the idea that lake changes in the now-dry region caused past quakes. However, researchers say, the timeline pulled from sediment in three deep trenches confirms that this portion of the fault is long past the expected time for a major temblor that would strongly shake the Los Angeles Basin.

The new study, appearing in the February issue of the Bulletin of the Seismological Society of America, doesn't change existing thinking about the threat of a major quake -- potentially measuring 7.0 to 8.0 on the Richter scale -- for southern California. It does, however, provide the first published documentation of much-discussed data that have emerged in the last three decades from an area that is now rapidly being built up and populated, just north of the Salton Sea.