A preliminary 3.9 magnitude earthquake shook the Sonoma County area Saturday morning.SONOMA COUNTY, Calif. (KGO) -- A preliminary 3.9 magnitude earthquake shook the Sonoma County area Saturday morning.The quake was reported at 7:05 a.m. about 3 miles southeast of The Geysers, according to the USGS. There were no reports of damage. Report a correction or typo