400-plus small quakes jolt California city in recent weeks

The U.S. Geological Survey says 435 small earthquakes have rattled the San Francisco Bay Area city of San Ramon in the last two weeks.

USGS research geophysicist Brad Aagaard says the have been recorded since Oct. 13. Most of them have ranged from magnitudes-2.0 to -3.0. The largest was a magnitude-3.6 on Oct. 19.

No damage or injuries have been reported.

San Ramon and other nearby cities sit on the Calaveras Fault and have a history of earthquake swarms. The USGS says they're not cause for extra concern and unlikely to lead to a large, damaging quake.

Based on other swarms, the agency predicts that the series of quakes may persist for several more weeks.

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Citation: 400-plus small quakes jolt California city in recent weeks (2015, October 27) retrieved 25 February 2024 from https://phys.org/news/2015-10-plus-small-quakes-jolt-california.html
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