A pre-dawn earthquake gave parts of Sonoma County an early wake-up call today, as a magnitude 3.7 temblor shook the hills near The Geysers at about 4:21 AM. The quick jolt sent in a flurry of shake reports, but so far, there have been no reports of injuries or structural damage.
Local outlets quickly reported the quake, and according to the Fresno Bee, an initial automated reading from the U.S. Geological Survey was later revised to a magnitude of 3.7 after review by seismologists. The epicenter was reported near the Geysers geothermal complex, with officials logging only a handful of felt reports early in the morning.
Where It Struck
Shake maps placed the epicenter roughly two miles southeast of The Geysers, near the Lake and Sonoma county line, with the quake’s depth listed as essentially at the surface. Shallow quakes like this can feel extra punchy close to the source, even when the magnitude is relatively modest. As of today, there were still no confirmed reports of damage or injury, according to SFGATE.
Why This Area Quakes Often
The Geysers geothermal field is one of the country’s most seismically active zones, and it is not just a result of natural fault lines. Steam extraction and the injection of condensed water for power production alter the pressure and stress in the rock below, which can increase the likelihood of small, shallow quakes. The U.S. Geological Survey notes that those industrial processes, combined with existing regional faults, are a key reason the area sees frequent minor tremors.
What To Do If You Feel It
During an earthquake, the recommended safety action is to “Drop, Cover, and Hold On,” according to the U.S. Geological Survey. If you felt any shaking, officials urge you to file a report through the USGS “Did You Feel It?” survey, which helps scientists map intensity and supports emergency planning.
Once the ground stops shaking, experts advise securing heavy items that could topple, checking for gas or water leaks, and remaining prepared for small aftershocks.
This latest jolt capped a run of shallow quakes in the same patch of the North Bay earlier in the week. Authorities had already logged a stronger event on Monday, recorded at roughly magnitude 4.1, according to KCRA. Officials have not reported any damage or larger aftershocks connected to Thursday’s quake at this time.
