SAN FRANCISCO - OCTOBER 17:  General view of the Marina district disaster zone after an earthquake, measuring 7.1 on the richter scale, rocks game three of the World Series between the Oakland A's and San Francisco Giants at Candlestick Park on October 17, 1989 in San Francisco, California.  Despite some discussion to cancel, baseball Commissioner Fay Vincent agrees to allow  the series to continue.  Play resumed October 25, and the A's go on to sweep the Giants in four games.  (Photo by Otto Greule Jr /Getty Images)

Earthquakes Underestimated in California

If you live in, or plan on living, in Southern California in the near future, take this as a note. There will be plenty of earthquakes (mainly small ones) that you will have to deal with on a consistent basis.

In a ten year period from 2008 and 2017, the southern part of California was hit by over 1.8 million earthquakes. This is 10 times more than previously thought, a new study found.

Seismologists at the California Institute of Technology found approximately 180,000 earthquakes had been recorded during that time.

The data from the daily recordings showed that the region experienced at least 495 quakes a day. or roughly one every three minutes. The reason that most of these earthquakes were missed was simply because they were just too small to notice, even for the best technology.

“It’s not that we didn’t know these small earthquakes were occurring,” said Zachary Ross, lead author of the study and soon to be assistant professor of geophysics at Caltech. “The problem is that they can be very difficult to spot amid all of the noise.”

The study about these earthquakes was published last Thursday in the peer-reviewed journal Science.

Researchers did state that it was hard to find the smaller quakes or temblors because seismic data also includes background noise such as building construction and shaking from traffic.

To find the quakes, seismologists used a technique called “template matching,” where an easily-identifiable earthquake signal is used as a template to find matching data indicating a temblor. Researchers also used an array of powerful computers to scan the earthquake catalog and verify the new earthquakes.

Most of the smaller temblors that were found by scientists were between negative 2.0 and 1.7.

In a statement, Michael Gurnis, director of the seismological laboratory and geophysics professor at Caltech, said the study “has opened a new window, allowing us to see millions of previously unseen earthquakes and this changes our ability to characterize what happens before and after large earthquakes.”

 

Photo from Time Magazine