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Several small aftershocks have been reported following a 4.0-magnitude earthquake that struck in Oakland this morning, according to the U.S. Geological Survey. 

The 4.0 quake was reported at 6:49 a.m. and was located in the Oakland hills about a mile north of Piedmont and 3 miles south of Berkeley, USGS officials said. The reported location is approximately at Lake Temescal, in Oakland near the Berkeley border. 

The quake had a depth of about 3.3 miles and struck on the Hayward Fault, which also saw a 4.0-magnitude earthquake on July 21 in Fremont. 

Several small aftershocks were reported in the hour after this morning's quake, the biggest of which was a 2.4-magnitude temblor in the same area at 7:40 a.m., according to the USGS. 

BART trains were briefly delayed by about 10 minutes this morning as a result of the 4.0 quake, which prompted crews to stop trains and inspect the tracks for possible damage. No damage was found and trains are back on regular service, BART officials said. 

The quake was reported across the Bay in San Francisco and on the Peninsula, as well as out in Concord and elsewhere in Contra Costa County and even as far away as Santa Cruz County.