According to the USGS, a 3.5 quake hit near the East Bay city of Danville Monday afternoon at 3:15 p.m. It was followed by a much smaller quake about 30 minutes later.
There was no immediate reports of damage.
The USGS Website said the earthquake was five miles deep. From the map on the site it appears the quake hit along the northern end of Calaveras fault.
One woman who lives near the epicenter said it felt like a car had run into her house.
We called the Safeway on Camino Tassajara and a worker there described the quake as if someone picked up the store and dropped it. The good news is that not even one pickle jar fell over.
Pickle jars are also safe at the Lunardi's on Railroad Avenue. Workers felt a "big shake" but says nothing fell from their shelves.
The Contra Costa Times reported one reader who lives in nearby Diablo called them to say that a few things fell from her shelves.
BART slowed its trains as a precaution following the quake.
The U.S. Geological Survey said the earth kept shaking overnight. A preliminary magnitude of 2.2 struck in Contra Costa County near Danville Tuesday morning.
According to the USGS, the earthquake occurred at about 12:35 a.m. and had a depth of about 4.7 miles.
The quake was centered 1 mile east-northeast of Danville and 11 miles south-southeast of Concord, which is the same area as Monday's shaker.