Two earthquakes struck near The Geysers in California’s North Bay, rattling homes across the region and drawing fresh attention to one of the state’s most seismically active zones. The larger event registered at magnitude 4.3, centered just 4 kilometers north-northwest of The Geysers, a geothermal field in Sonoma County. The pair of quakes, recorded in rapid succession, sent shaking reports flooding in from communities across the North Bay and into parts of the wider Bay Area.
Magnitude 4.3 Quake Strikes Near The Geysers
The stronger of the two events, cataloged by the U.S. Geological Survey under event ID nc75316827, placed the epicenter 4 km NNW of The Geysers in Northern California. The USGS event record includes origin time, hypocenter and epicenter coordinates, depth, and the current preferred magnitude after standard revisions. A second, smaller quake struck the same area shortly before the 4.3 event, forming the pair that residents felt in quick succession. Insufficient data exists in the verified source set to confirm the exact magnitude or dedicated event page for the second quake, though USGS catalog queries support its occurrence in the same narrow time window and geographic footprint.
Crowd-sourced felt reports collected through the USGS “Did You Feel It?” system were quickly converted into what the agency calls Community Determined Intensity, or CDI, values. Those mapped intensity patterns show that shaking extended well beyond the sparsely populated Geysers area, reaching communities across the North Bay and into the broader Bay Area. The quantitative felt-report data offers a more precise picture of impact than anecdotal social media posts alone, giving emergency managers and seismologists a structured view of how far and how strongly the ground moved.
Why The Geysers Keeps Shaking
The Geysers is not just any fault zone. It is the largest complex of geothermal power plants in the world, and the frequent small earthquakes recorded there are tied directly to energy production. According to a USGS explainer on Geysers seismicity, the area experiences thousands of small quakes each year, most of them induced by the injection of wastewater back into underground reservoirs as part of geothermal operations. That process increases pore pressure in surrounding rock, which can trigger slip along pre-existing fractures. The USGS draws a clear distinction between these induced events and the larger tectonic hazards posed by regional fault systems such as the San Andreas and Rodgers Creek faults.
Historical seismicity maps compiled by the USGS in Open-File Report 02-209, covering the Santa Rosa quadrangle from 1969 through 1995, show dense clustering of earthquake activity around The Geysers with time-dependent relationships to geothermal production levels. The report includes enlarged map sheets that reveal how seismicity near Santa Rosa, Healdsburg, and the broader Geysers region tracked changes in fluid injection over decades. That long record makes clear that the area’s earthquake activity is not random but closely linked to industrial operations, a pattern that has persisted since large-scale geothermal development began in the 1960s.
Geothermal Energy and Earthquake Risk: A Persistent Tension
Most coverage of Geysers earthquakes treats them as minor curiosities, brief shakers that rattle dishes and fade from the news cycle within hours. That framing misses a real tension. The Geysers supplies renewable baseload power to Northern California, but the induced seismicity it generates raises legitimate questions about how much shaking nearby communities should be expected to absorb. A magnitude 4.3 event is not catastrophic, yet it is large enough to be felt across a wide area and strong enough to cause minor damage in structures close to the epicenter. The distinction between “induced” and “tectonic” earthquakes, while scientifically important, offers little comfort to a homeowner in Cloverdale or Middletown who feels the floor move at 2 a.m…