LOS ANGELES — Certain earthquake fault segments long thought to be stable may rupture and cause a mega-quake, suggests a new study.
That's what happened during the 2011 magnitude-9 quake in Japan that triggered a tsunami and during the 1999 magnitude-7.6 Chi Chi quake in Taiwan.
In both cases, scientists assumed that "creeping" sections of a fault would serve as a buffer and prevent the entire fault from unzipping. But a new study published online Wednesday in the journal Nature suggests this may not always be the case.
Combining computer modeling and fieldwork, researchers at the California Institute of Technology and Japan Agency for Marine-Earth Science and Technology found that creeping segments sometimes snapped, resulting in a bigger quake than anticipated.
This may have important implications for California's San Andreas Fault, which has a creeping section that separates the locked segments in Northern California and Southern California.