The U.S. Geological Survey is reporting an earthquake with a preliminary magnitude of 2.1 struck this morning in Sonoma County.

At 3:17 a.m., the quake shook an area one mile north-northeast of The Geysers, according to the USGS, and had a depth of 2.4 miles.

The epicenter was located 12 miles east of Cloverdale, according to the USGS.

In the past seven days, 29 earthquakes of magnitude 2.0 or larger have occurred around The Geysers, with three of those occurring within the past 24 hours.

The Geysers is the largest single geothermal field in the world, according to the U.S. Department of Energy, and the region experiences constant seismic events between 0.5 and 3.0 on the Richter scale.

Deep-well injection at the site, which the Department of Energy says is necessary for the extended and sustained production of geothermal resources at the site, is believed to fuel the region's seismicity.

The largest event recorded in The Geysers field was a magnitude 4.6 quake in 1973, according to the Department of Energy.

There are 22 active geothermal plants in the region that produce roughly 950 megawatts of power, or enough for about 950,000 homes.



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