Recent Earthquakes Tripled The Chance Of Big Quake On The San Andreas Fault

A new study found that last year's earthquakes in Ridgecrest, California, tripled the risk of a major earthquake along the San Andreas fault. The quakes, which had magnitudes of 6.4 and 7.1, caused at least $1 billion in damage and left one person dead.

The likelihood of a massive earthquake along the San Andreas fault in the next 12 months is now just over 1%. The study also found that the chance of an earthquake along the Garlock fault, which runs along the northern edge of the Mojave Desert, increased by 100% from .023% to 2.3%.

That concerns scientists because the Garlock fault is perpendicular to the San Andreas fault. If a large quake occurs on the Garlock fault, it could trigger a bigger earthquake along the San Andreas fault.

"The Garlock is the link in the chain," Dr. Ross S. Stein, a former United States Geological Survey geophysicist, told the New York Times. "If it comes within about 25 miles of the San Andreas, it increases the chances of an earthquake there by about 150 times."

While the Garlock fault runs through a sparsely populated area, a major earthquake along the San Andreas fault could devastate more densely populated areas of California, such as Los Angeles.

Despite the increased risk of a massive earthquake, Dr. Stein said the chances are still slim.

"The sky is not falling," he said. "Nobody should panic."

"But at the same time, the inference that the San Andreas likelihood of rupture has increased should be a reminder that anybody in Los Angeles should ask themselves, 'Am I ready?'"

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