East Bay News

Earthquake swarm shakes East Bay

Wednesday, November 13, 2013

There's been a lot of shaking going on in southern Contra Costa County the past few days. There's been a swarm of small earthquakes along the Calaveras Fault, centered primarily around San Ramon and Danville.

The experts say all these little earthquakes are not predictive of anything. According to a UC Berkeley seismologist, the earthquakes in Danville and San Ramon are not precursors or aftershocks, just a swarm.

In the San Ramon Valley, there have been four measurable quakes since Oct. 21 with a magnitude of 2.9 or greater. Wednesday morning there was a minor earthquake with a preliminary magnitude of 3.4, according to the U.S. Geological Survey.

"In the case of a swarm, we think of all the earthquakes, popping, popping and then maybe a bigger one and maybe more smaller ones and then maybe another bigger one," UC Berkeley seismologist Peggy Hellweg said.

The swarms of small quakes are not uncommon since the Calaveras Fault system runs right underneath Interstate 680.

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earthquake, san ramon, danville, USGS, uc berkeley, east bay news, laura anthony
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