Thursday, September 15, 2011

California's tectonic vulnerability: the big one is expected any time

san-andreas-fault-map by trudeau
san-andreas-fault-map, a photo by trudeau on Flickr.

Plates that will crack in a spectacular and nation-affecting way: the San Andreas Fault in California

A number of experts say that California is due for a large earthquake; likely a quake that would emanate from the San Andreas fault line, which runs under much of Southern California.

During such an earthquake, waves would become trapped in the sediment underneath Los Angeles, causing 7.8-level tremors that could shake the area for up to two minutes, says the University of Southern California Daily Trojan.

The seismic waves are unpredictable, so logistics of exactly where this earthquake will hit cannot be specified. The Uniform California Earthquake Rupture Forecast, however, believes Los Angeles does face a 67 percent chance of a 6.7-magnitude earthquake or greater sometime in the next 30 years. The chance of a similar quake striking anywhere in California in the same time frame is 99.7 percent.

Jordan noted that California is not bracing itself for a specific earthquake, but that there are many possible “big ones.” Though the San Andreas fault is the most likely source of “the big one,” Jordan said there are other faults that could spark dramatic seismic activity in the region.

USC has quite a program for earthquake preparedness. Protective activities are practiced on campus and there are contingencies for water and shelter.