Thread: San Diego County shaken by a 4.9 earthquake on a dangerous fault near Anza

San Diego County shaken by a 4.9 earthquake on a dangerous fault near Anza

[A 4.9 earthquake occurred on the San Jacinto fault system on Friday night, shaking San Diego County.
(USGS)

Scientists studying which fault produced it

By GARY ROBBINS
APRIL 3, 2020 7:02 PM

A magnitude 4.9 earthquake occurred at 6:53 p.m. on Friday near Anza, shaking parts of San Diego County hard, said the U.S. Geological Survey. The temblor also was felt in downtown Los Angeles.

The epicenter was located 11 miles east-southeast of Anza and 16 miles north-northeast of Warner Springs at a depth of 6.6 miles.

The quake appears to have been produced by the San Jacinto fault system, according to Tom Rockwell, a geologist at San Diego State University.

“This is a moderate earthquake in an area that has produce a lot of moderate earthquakes,” Rockwell said. “This is section of the fault where we expect larger faults. The last Nov. 22, 1800 we had a 7.3 earthquake. It produced up to 13 feet of lateral displacement near Anza.”

The average return time of a big quake is 270 years. “Could be have one tomorrow; yes,” said Rockwell. “Could it wait another 100 years, yes.”

The San Jacinto is one of the most restless fault systems in Southern California and is capable of producing quakes greater than 7.3 to 7.5.

Strong aftershocks to Friday’s quake are expected.

https://www.sandiegouniontribune.com...xxx-earthquake

The 4.9 earthquake near Anza produced an aftershock Sunday felt in greater San Diego

A magnitude 3.5 aftershock to Friday’s 4.9 earthquake near Anza was felt in San Diego County on Sunday. (USGS)

Seismologists say the seismic activity is occurring on the San Jacinto fault system

By GARY ROBBINS
APRIL 5, 20204:09 PM

The magnitude 4.9 earthquake that occurred near Anza on Friday evening produced an apparent 3.5 aftershock on Sunday that was felt across much of San Diego County.

The US Geological Survey said Sunday’s quake occurred at 3:37 p.m. at a spot 11 miles east-southeast of Anza and 17 miles north-northeast of Warner Springs. The temblor started at a point 8.2 miles deep in the earth, which is common for that area.

San Diego State University seismologist Tom Rockwell said the seimsic activity has been occurring on the San Jacinto fault, an active system that is capable of producing quakes in the 7.3 to 7.5 range.

The USGS said Sunday it received reports that the aftershock was felt in Valley Center, Borrego Springs, Escondido, Ramona, Fallbrook, San Marcos, El Cajon, Carlsbad, San Diego, Apline, La Mesa, La Jolla, Julian, Lakeside, and Poway.

https://www.sandiegouniontribune.com...n-diego-county

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