HEALDSBURG (CBS SF) — A 4.1 magnitude earthquake rattled through an area near the Geysers north of Santa Rosa near Cobb Mountain early Wednesday morning, officials said.

According to the U.S. Geological Survey, the quake struck at 4:57 a.m. at a depth of 2.1 kilometers and was felt by residents in Healdsburg, Kelseyville and Middletown.

Most residents reported to the USGS that they had been awaken by a moderate jolt. There were no reports of damage.

The Geysers region is the location of a large PG&E geothermal complex and known for its seismic activity. Quakes in the range of 4.0 to 4.5 are not uncommon.