Any time there’s a magnitude 8.0 earthquake, you’d expect a nearby city to get walloped. But according to a brand new simulation of what would happen if the “Big One” hit the San Andreas fault in southern California, the shaking would be particularly severe and last much longer in Los Angeles than in other parts of the region.
Using the world’s fastest supercomputer, Thomas Jordan of the University of Southern California and a team of researchers simulated how the ground would shake throughout Southern California and into Mexico in the event of a magnitude 8.0 earthquake centered northwest of Los Angeles.
The team found that the ground beneath the city shakes harder and longer than surrounding areas, likely because of soil effects that amplify seismic waves. This means that buildings in L.A. have to put up with much more punishment.
As the above news report from KTLA mentions, this result is doubly interesting because scientists recently found evidence that big earthquakes on the southern part of the San Andreas happen far more often than anyone thought:
They found that strong earthquakes — between 6.5 and 7.9 magnitude — shook the area every 45-144 years, instead of the previously established 250-400 years. Since the last big 7.9 magnitude earthquake struck southern California in 1857, or 153 years ago, scientists believe the next “Big One” could happen at any time. The scientists on Friday provided an abstract of their study, which will be published in full in the September 1 issue of the magazine Geology.
“What we know is for the last 700 years, earthquakes on the southern San Andreas fault have been much more frequent than everyone thought,” said the study’s lead author Sinan Akciz.
This doesn’t mean that a powerful earthquake is imminent; scientists cannot predict earthquakes. What it does mean is that anyone living in southern California should make sure they have an emergency plan and supplies in place in case the unthinkable — but certainly possible — happens.