Yeah, it's a little one but 2 in one day is a little freaky.
http://www.sfgate.com/cgi-bin/articl...BAJM1LKI5A.DTL
2nd earthquake - aftershock - rattles Bay Area
Vivian Ho, Chronicle Staff Writer
Thursday, October 20, 2011
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(10-20) 21:01 PDT BERKELEY -- An earthquake measured at magnitude 3.8 struck the Hayward fault near Berkeley at 8:16 p.m. Thursday, the U.S. Geological Survey said.
The agency said it was the aftershock to the 4.0 quake that occurred just hours before in the same area.
The second quake was centered one mile east of Berkeley and was felt throughout the East Bay and San Francisco.
BART delayed service by 15 minutes after the quake.
In Oakland's Montclair District, the evening quake rattled the dinner crowd, particularly at Italian Colors on Mountain Boulevard, where a piece of plaster fell from the ceiling.
"It was three inches by five," said Michael Modos, the manager. "It was pretty dramatic."
Police reported no damage in Berkeley, nor any reports of serious damage in Oakland.
Although U.S. Geological Survey experts have officially determined from the location and depth that the second quake was the aftershock of the first one, geophysicist Rafael Abreu warned people not to get too complacent.
"When you have an area with such an active seismicity, it's hard to tell if you're really seeing if there's an aftershock or if it's just a regular earthquake," he said. "You should be prepared for more earthquakes to happen, whether they're aftershocks or not."
The earlier quake struck the Hayward Fault near Berkeley at 2:41 p.m.
The quake was centered 2 miles southeast of Berkeley, the agency said, and was widely felt in the East Bay and San Francisco.
There were no reports of damage from that quake. BART delayed trains for 15 minutes while workers examined the system. They found no problems.
"My hands are still shaking - my heart is just slowing down," Krys Freeman, a web manager for Greenbiz in Oakland, said minutes after the quake rattled her office on the eighth floor of a building at Frank Ogawa Plaza. "I'm afraid of heights, so I was thinking of exit strategies."
The quake may have felt stronger to many in the East Bay than its 4.0 magnitude would suggest because the epicenter was deep beneath the surface, about 6 miles, said Jack Boatwright, a seismologist for the U.S. Geological Survey.
"The path is very simple from a deeper quake," he said. "That simple path means it is felt very abruptly and very sharply, and that's why people felt it so strongly."
The quake was the same day as an annual Great California ShakeOut state earthquake preparedness exercise.
"You couldn't get any more 'ShakeOut' than this," Abreu laughed "I guess it was lending more credibility to the exercise."
Chronicle staff writers Carolyn Jones, Will Kane, Nanette Asimov and Allen Matthews contributed to this report.
E-mail the wrtiers at
cjones@sfchronicle.com,
wkane@sfchronicle.com,
amatthews@sfchronicle.com,
nasimov@sfchronicle.com and
vho@sfchronicle.com.
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