The USGS says the first quake, a magnitude 3.2, was centered east of Highway 242 in Concord and struck at about 7:01 a.m. PDT Wednesday. The second and largest, a 3.6-magnitude, struck at 7:32 a.m. It was later downgraded to a 3.5. The third, a 2.6-magnitude, hit shortly after at 7:35 a.m.

Over 100 people, mostly in Pleasant Hill, reported feeling the earthquakes, according to USGS' online "Did You Feel It" survey.

There have been no reports of injury or damage.

Aftershocks continue to rattle the East Bay after a 3.6-magnitude earthquake struck the same area on Sunday afternoon.

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 Wednesday.

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.