4.7 Earthquake in California
 

Southern California earthquake largest in greater L.A. since 2010

LATimes, March 11, 2013


http://earthquake.usgs.gov/earthquak...96281_ciim.jpg

The magnitude-4.7 earthquake that rattled Southern California on Monday was the largest centered in the greater Los Angeles area since 2010, officials said.

“It’s been three years since we had anything this size this close to Los Angeles,” said Susan Hough, a seismologist with the U.S. Geological Survey. She cited a magnitude-5.4 quake that struck the desert area in July 2010.

Since then, Southern California has experienced quakes larger than Monday's but they occurred closer to the U.S.-Mexico border.

Monday's quake was preceded by a small foreshock, which confused the survey’s monitoring system into recording multiple shocks of various sizes. The temblor was centered a few miles northeast of the San Jacinto fault, Hough said.

The quake struck at a depth of 7 to 8 miles, about 2 miles deeper than a typical quake, Hough said. Deeper quakes cause vibrations to travel farther and are less likely to create aftershocks, she said.

People as far away as Sequoia National Park, about 250 miles away, reported feeling the quake. There were no reports of damage or injuries in the Southland.

Officials initially reported three moderate temblors -- the largest being a magnitude 5.2. Since then, officials said there was only one quake, measuring 4.7 near Anza in Riverside County.

There have been more than 60 aftershocks since then, all relatively small.

“It was a pretty good shake up here.” said Capt. Daniel Heiser of the Riverside County Fire Department.
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I had warned about the increase in earthquakes in California over the past 2 months, in my Earthquake Thread, in this section.

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