VALLEJO (CBS SF) – An earthquake with a magnitude of 3.5 shook Solano County and nearby regions Thursday morning, less than 24 hours after a quake of similar magnitude rattled the area, according to the U.S. Geological Survey.
The quake struck at 9:13 a.m. and was centered about 2 miles south of Vallejo, according to the USGS. Shaking could be felt in other Bay Area cities, including Martinez.
The earthquake had a depth of 5.7 miles. The initial magnitude was recorded as 3.7, but was revised a short time later to 3.5.
Vallejo Police Sgt. Jeff Bassett said he’s seen no immediate reports of injury or damage. He described the quake as “quick and abrupt,” only lasting about one second.
Another 3.5-magnitude quake struck Wednesday at 6:09 p.m., and its epicenter was located 3 miles south of Vallejo, according to the USGS.
Sue Simon, the assistant to the Vallejo city attorney, said she felt both.
“It was a small jolt then a big jolt,” Simon said of Thursday morning’s quake.
She said the jolts were about a half-second apart, and that she felt them from City Hall.
“I was told the large windows in the building flexed out a little,” Simon said.
The USGS has received responses from throughout the Bay Area about the quake, most of them from the cities of Vallejo, Benicia, Napa, American Canyon and Martinez.
Richard Allen, director of the Seismological Laboratory at the University of California at Berkeley, said he felt the “weak shaking” Thursday morning that lasted a less than a second.
He said it occurred close to the continuation of the West Napa Fault, which runs east of Santa Rosa southeast to Vallejo and is parallel to the Rodgers Creek and Hayward faults.
Because both quakes were of magnitude 3.5, he considers them a cluster. If Thursday morning’s quake had been of a lesser magnitude, it would be considered an aftershock, Allen said. Both quakes had a depth of 5.7 miles, Allen said.
Clusters are not that unusual, Allen said, noting that there were three or four small quakes in Berkeley in October.
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