Latest news with #Geysers
CBS News
3 days ago
- Science
- CBS News
Why are there so many earthquakes at The Geysers Northern California geothermal field?
An earthquake swarm that rattled an area of Northern California early Thursday was another round of recurring temblors in a seismically active region that is home to the world's largest geothermal field. The Geysers Geothermal Field, located about 72 miles north of San Francisco, covers some 45 square miles among Lake, Mendocino and Sonoma counties. According to the U.S. Geological Survey, the activities associated with harnessing the steam to generate electricity cause frequent, minor earthquakes in the region. The quakes can be felt by those who work among the 18 geothermal power plants and by nearby residents. Seismologists offer several explanations for why earthquakes are induced at The Geysers. The withdrawal of steam and heat from the field causes the surrounding rock to contract, which can trigger quakes from the contractional stresses. Pumping reclaimed water back into the steam reservoirs is also a factor because of the thermal contrast between the cold returned water and the hot surrounding rock. In addition, the hydraulic pressure of the injected water may be finding its way into faults, facilitating fracturing due to increased fluid pressures, according to the USGS. No large continuous fault line is known to exist at The Geysers, but there are numerous small fractures in the rock located near the many steam and injection wells, the agency says. The activities cause local stress changes that, combined with regional tectonic stresses, induce the quakes on these small faults. Most of the major seismic hazards in Northern California are from large earthquakes that strike along regional faults miles away from The Geysers, such as the San Andreas and Healdsburg-Rodgers Creek faults. The largest quake recorded at The Geysers is approximately M4.5, and while it's possible that a magnitude 5 could occur, larger earthquakes are thought to be unlikely, the USGS said. The Calpine Corporation, which owns and operates 13 plants at The Geysers, says the field's current capacity is 725 megawatts of electricity around the clock, enough to power 725,000 homes. Energy generated at The Geysers totals about 25% of California's renewable energy and about 40% of all geothermal electricity generated in the U.S., according to the National Association of Regulatory Utility Commissioners.
CBS News
4 days ago
- Climate
- CBS News
Earthquake swarm recorded near Northern California geothermal field
A series of moderate to minor earthquakes struck near the geologically active area in Northern California known as The Geysers south of Clear Lake Thursday morning. The earthquake swarm started just before 6 a.m., according to the U.S. Geological Survey, with the largest magnitude being a 4.0. At least four other aftershocks have been recorded, with magnitudes ranging all just under 3.0. According to USGS, the largest quake should have been felt throughout Lake and Sonoma counties. There have been no reports of damage at this time.
CBS News
31-05-2025
- Climate
- CBS News
North Bay hit by earthquake with preliminary magnitude of 3.4
An earthquake struck in the North Bay on Saturday morning, according to the United States Geological Survey. The quake had a preliminary magnitude of 3.4 and was about .6 miles north-northwest of The Geysers. It had a depth of about 1.8 miles. Some weak shaking was reported by people in Healdsburg and in San Rafael.
