Southern Calif. Has one every 3 minutes: study

According to a new study, between 2008 and 2017, southern California was hit by 1.8 million earthquakes, 10 times more than expected.

Seismologists at the California Institute of Technology have discovered that about 180,000 earthquakes have been recorded during this period.

The data showed that the region was experiencing 495 earthquakes per day, about one every three minutes. However, the reason these earthquakes have just been discovered is that they are too small to be noticed.

"It's not that we do not know that these small earthquakes were occurring," said Zachary Ross, lead author of the study, who will join the Caltech faculty in June as assistant professor of geophysics. in a statement. "The problem is that they can be very difficult to spot despite all that noise."

The study was published Thursday in the peer-reviewed journal.

Researchers say that temblors are hard to find because seismic data also includes background noise such as building construction and traffic shaking.

To find earthquakes, seismologists used a technique called "pattern matching", in which an easily identifiable earthquake signal is used as a template to find match data indicating a temblor. The researchers also used a set of powerful computers to scan the catalog of earthquakes and check for new earthquakes.

Scientists have stated that most of the smaller models found were between negative magnitudes of 2.0 and 1.7.

In a statement, Michael Gurnis, director of the seismology laboratory and professor of geophysics at Caltech, said the study "has opened a new window allowing us to see millions of earthquakes never seen before, which is changing our capacity to characterize what happens before and after major earthquakes. "

Follow Brett Molina on Twitter: @ brettmolina23.

Read or share this story: https://www.usatoday.com/story/news/nation/2019/04/19/hidden-earthquakes-southern-calif-has-one-every-3-minutes-study/3517845002/