Scientists have long assumed that a mega-quake along the San Andreas fault that could be felt from San Diego to San Francisco was widely considered impossible. But a new study suggests otherwise.

A key fault segment near the Central California city of Paso Robles might not serve as a barrier in all cases, researchers wrote in the online edition of the journal Nature.

Using a combination of laboratory measurements and computer simulations, the two scientists showed how so-called creeping segments in a fault — long thought to be benign because they slip slowly and steadily along as tectonic plates shift — might behave like locked segments, which build up stress over time and then rupture.

Kenneth Hudnut, a geophysicist at the U.S. Geological Survey in Pasadena who was not involved in the research, said that the study sounded "a warning message."

Hudnut emphasized that an extreme quake powerful enough to blast through the supposedly stable midsection of the San Andreas was unlikely.

But if one did strike, he said, it might put unexpected strain on California's emergency response systems. Planners had always assumed that responders from one part of the state would be available to supply aid in the other. (Source: Los Angeles Times)

Story Date: January 18, 2013