Southern San Andreas fault waiting to explode

really hate posting this Especially living in California/

Southern San Andreas fault waiting to explode
Expert believes Los Angeles area at risk for massive earthquake

Reuters
Updated: 23 minutes ago

LONDON - The southern end of the San Andreas fault near Los Angeles, which has been still for more than two centuries, is under immense stress and could produce a massive earthquake at any moment, a scientist said Wednesday.

Yuri Fialko, of the Scripps Institution of Oceanography at La Jolla, Calif., said that given average annual movement rates in other areas of the fault, there could be enough pent-up energy in the southern end to trigger a cataclysmic jolt of up to 32 feet (10 meters).

"The observed strain rates confirm that the southern section of the San Andreas fault may be approaching the end of the interseismic phase of the earthquake cycle," he wrote in the journal Nature.

A sudden lateral movement of 23 to 32 feet (7 to 10 meters) would be among the largest ever recorded.

http://www.msnbc.msn.com/id/13457472/

On edit: Here's the Nature link:http://www.nature.com/news/2006/060619/full/060619-5.html

Published online: 21 June 2006; doi:10.1038/news060619-5
Southern California due major earthquake
Large buildup of strain in the San Andreas fault makes quake imminent.
Alexandra Witze

Southern California could be in line for a serious quake along the infamous San Andreas fault, seismologists have found. New measurements suggest that the region close to Los Angeles, the traditional earthquake location in Hollywood disaster movies, could feel the effects of a real-life tremor within the next few years.

The southern part of the San Andreas seems to be building up a considerable amount of strain, the work suggests. And because no significant earthquake has ruptured this portion of the fault for at least the past 250 years, it could be primed to cause a devastating event.

"It could be tomorrow; it could be ten years from now," says Yuri Fialko, a geophysicist at the Scripps Institution of Oceanography in San Diego, California, who led the study. "But it appears unlikely to accumulate another few hundred years of strain."

Some scientists had suggested that the San Andreas could be releasing strain slowly over time, by 'creeping' along its length, or by transferring some of the strain on to neighbouring faults. But the new study suggests that neither of these processes is occurring to a significant extent.

Taking the strain

Fialko gathered eight years' worth of radar data from European Space Agency satellites that measure in detail how the ground moves. He also added 20 years' worth of data from global-positioning measurements on the ground.

Taken together, he says, the measurements suggest that the two plates either side of the southern San Andreas are slipping past each other at around 25 millimetres per year. Without a recent earthquake to alleviate that strain, Fialko says, the fault line itself, which has remained essentially static for centuries, has built up between 5.5 and 7 metres of 'slip deficit'.

If released all at once, that could result in a magnitude-8.0 earthquake, he says, roughly the size of the devastating 1906 quake in San Francisco. Such a powerful event might threaten even those buildings constructed to earthquake specifications.

Surprisingly, the study indicates that strain is building up differently on each side of the San Andreas. The rock on the North American side seems to be moving more flexibly, whereas the Pacific side acts more rigidly, says Fialko.

Link here