ANGWIN (CBS SF) — A 3.6 magnitude earthquake rattled wine country near Angwin early Monday morning, but there were no immediate reports of damage in the region.

According to the U.S. Geological Survey, the quake struck at 6:38 a.m. in the mountainous region 9 miles east of Angwin near Lake Berryessa. Immediately, residents in Napa, St. Helena, Vacaville and Calistoga told the USGS they felt the temblor.

Another 2.2 magnitude followed before 9 a.m.

The region is under an unrelated Red Flag Fire weather warning that has triggered PG&E to cut off electrical power to hundreds of local residents.

There were no immediate reports of damage or injury.