Oct. 20--A swarm of more than 200 earthquakes have rumbled through San Ramon in the Bay Area in recent days, including a 3.5 temblor Monday afternoon, according to the U.S. Geological Survey.
The biggest quake in the area in the past 24 hours was a magnitude 3.6 that struck about 4:20 p.m. Monday about one mile northeast of San Ramon. Shaking was felt as far as 14 miles away in Walnut Creek, the USGS reported.
Nearly 60 earthquakes, most of them so small they can't be felt, have rumbled beneath San Ramon since Monday morning. But looking further back, the town has seen 238 earthquakes since Oct. 13, some of them coming just minutes apart. Besides Monday afternoon's temblor, two others quakes were above magnitude 3.0.
Still, the swarm of quakes is not necessarily anything unusual. Susan Garcia, a spokeswoman for the USGS's Earthquake Science Center in Menlo Park, told the San Francisco Chronicle it's a positive sign that all the quakes were under magnitude 4.0.
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Earthquake swarms aren't unusual for the area, and they could continue for days or weeks, she said.
Swarm are more common in other parts of California, including Mammoth Lakes and the Imperial Valley.
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