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8 Aftershocks Rattle Concord Fault Since 3.6-Magnitude Quake Sunday

CONCORD (CBS SF) -- Small aftershocks continue to rattle the East Bay after a 3.6-magnitude earthquake struck Concord Sunday.

The U.S. Geological Survey says an earthquake with a preliminary magnitude of 4.0 hit at 2:13 p.m. Sunday.  That quake was later downgraded to a 3.6 by the USGS. It was centered a mile south of Concord, along the Concord fault.

Following the 3.6 quake, at least eight aftershocks were reported as of Tuesday.

1.8 -- 05/05 05:51 a.m.
2.8 -- 05/04 6:52 p.m.
1.6 -- 05/04 1:52 a.m.
1.5 -- 05/03 9:30 p.m.
2.3 -- 05/03 6:54 p.m.
1.6 -- 05/03 3:56 p.m.
2.1 -- 05/03 3:28 p.m.
3.0 -- 5/03 3:14 p.m.

Scientists says the Concord fault, which runs through Concord to Suisun Bay, has the potential to do major damage in the East Bay.

The Hayward and San Andreas faults steal most of the spotlight, but the Concord fault stretching from the Mount Diablo foothills to the Carquinez Strait could cause major damage due to its location.

"If we saw a 6.0 on Concord, we could see far more damage than we did in Napa," USGS Seismologist Dr. David Schwartz told KCBS news following Sunday's quake.

Even if the Concord Fault only produced a 5.0 quake, it could cause significant damage to refineries in the area.

There was a damaging 5.4-magnitude quake in 1955 that killed one person and caused property damage estimated at $1 million.

The USGS estimates there's a 3 to 4 percent probability of a magnitude-6.7 or higher earthquake striking on the Concord of lower Green Valley Fault in the next 30 years compared with 6.4 percent for the San Andreas and 14.3 percent for the Hayward Fault.

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