LOS ANGELES (CBSLA) — The Big One could be triggered by the energy on a series of small faults, new research has found.
The morning of the Fourth of July, a magnitude-6.4 earthquake struck near the city of Ridgecrest, which was rocked 34 hours later by a bigger quake – a 7.1.
Caltech researchers now say those two earthquakes, which were felt throughout Southern California and in Nevada, weren’t produced by just one fault – they were the result of 20 or more faults releasing energy seconds apart. The energy from all those faults combined to create those two strong earthquakes.
“In hindsight, if we really look back at the last century, all the largest events in California that we had, probably most of these events look like this Ridgecrest sequence than the 1906 San Francisco earthquake,” said Zach Ross, lead author of the new study.
Improved technology has made it possible to get a better understanding of an event like the Ridgecrest earthquake.
“We can look at how the ground moves, between those two images. So, we can see that there are many of these faults that have cracked the surface, they went all the way up,” Ross said. “But then we can also use our seismic instruments that record the ground motion.”
Micro quakes occur throughout California every day, but don’t always lead to a major earthquake. How does energy on one small fault lead to a major earthquake? One rupture can lead to another, much like a line of dominoes.
“Once there’s a fault that starts to rupture somewhere, then it’s kind of easy to just keep triggering more and more faults nearby,” Ross said.
The study was originally posted in the journal, “Science.”