A magnitude 3.0 earthquake was measured early Thursday morning at American Canyon, nearly 10 miles south of Napa, according to the U.S Geological Survey's website.
The earthquake happened at 3.56 a.m. at a depth of 6.8 miles.
Sheriff's officials say there have been no reports of damage or injury.
The region has experienced a series of aftershocks since the
ABC7 in San Francisco reported it was the second quake in the Bay Area in less than 9 hours. A 2.9 earthquake occurred near Palo Alto Wednesday night.