Valley News -

4.4 magnitude earthquake felt in Temecula Valley


Last updated 8/29/2018 at 9:32am

At about 7:33 p.m. tonight, an earthquake magnitude 4.4 struck at a depth of 3.7 miles and just about 3 miles north of La Verne, according to the U.S. Geological Survey. Less than a minute later, another shaker measuring 3.4 hit the same area.

The quake was felt in the Temecula Valley. So far, no damage has been reported in the area. There were no reports of damage in Los Angeles or La Verne, police in both cities said.

Seismologist Lucy Jones said the quake should not be expected to have done damage to structures.

Jones said the quake was not on the Sierra Madre fault, one of the largest in the region, but on an ancillary structure. The earthquake was the largest in Southern California since Dec. 29, 2015, when a magnitude-4.3 quake struck near Devore, in San Bernardino County, Jones said.

"This is a very ordinary earthquake for California, the size that we have several times a year somewhere in the state,'' Jones said.

More than a dozen small aftershocks were felt and as is always the case, there was about a 5 percent the largest magnitude-4.4 earthquake would be followed by a bigger one, Jones said.

California's nascent earthquake early-warning system had another successful run Tuesday night in response to the shaker, the Los Angeles Times reported Wednesday. Jones told reporters that the system sent out a warning three seconds before the shaking began.

The earthquake early-warning system is under development by the U.S. Geological Survey and is only available to a limited array of testers, but it is expected that more people will be eligible to test the system later this year, The Times reported.

It works on a simple principle: The shaking from an earthquake travels at the speed of sound through rock, which is slower than the speed of today's communications systems. For example, it would take more than a minute for a magnitude 7.8 earthquake that starts at the Salton Sea and travels up the state's longest fault, the San Andreas, to shake Los Angeles, 150 miles away.

An early-warning system would give L.A. residents crucial seconds, and perhaps even more than a minute, to prepare.

A seismic early-warning system for the West Coast has been under development for years by the USGS, the nation's lead earthquake monitoring agency, but the project has remained short of funds.

The USGS has said it planned to begin issuing limited public alerts from the system by the end of this year, as long as funding wasn't cut. Southern California is one area where the network of seismic sensors is dense enough at present to begin early warnings.

Jeff Pack contributed to this report.


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