LOS ANGELES (AP) — Certain earthquake fault segments long thought to be stable may rupture and cause a mega-quake, suggests a new study that could have implications for California's mighty San Andreas. 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.