The U.S. Geological Survey says a magnitude 3.9 quake hit at 5:38 a.m. Sunday about 24 miles north of Santa Rosa, or about 80 miles north of San Francisco
USGS geophysicist Don Blakeman says a second quake with a preliminary magnitude of 2.8 hit at 8:24 a.m. in the same area. Blakeman says the second earthquake was likely an aftershock to the first quake.
A dispatcher with the Santa Rosa Sheriff's Department says they had no calls reporting damage or any injuries.
The area where the earthquakes hit is near the Geysers geothermal development, a region that experiences frequent seismic activity.