The big one

Get those emergency supplies ready. Caltech scientists working with the United States Geological Survey have modeled the next big quake based on last week's temblor in China. Here's their scenario for a 7.8 magnitude event along the San Andreas fault in Southern California:

_10 a.m.: The San Andreas Fault ruptures, sending shock waves racing at 2 miles per second.

_30 seconds later: The agricultural Coachella Valley shakes first. Older buildings crumble. Fires start. Sections of Interstate 10, one of the nation's major east-west corridors, break apart.

_1 minute later: Interstate 15, a key north-south route, is severed in places. Rail lines break; a train derails. Tremors hit burgeoning Riverside and San Bernardino counties east of Los Angeles.

_1 minute, 30 seconds later: Shock waves advance toward the Los Angeles Basin, shaking it violently for 55 seconds.

_2 minutes later: The rupture stops near Palmdale, but waves march north toward coastal Santa Barbara and into the Central Valley city of Bakersfield.

_30 minutes later: Emergency responders begin to fan across the region. A magnitude-7 aftershock hits, but sends its energy south into Mexico. Several more big aftershocks will hit in following days and months.

Major fires following the quake would cause the most damage, said Keith Porter, of the University of Colorado.

Here's the latest quake map depicting western China