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Clear Lake Volcanic Field

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Clear Lake Volcanic Field is located about 90 miles north of San Francisco, California.

Quick Facts

Location: California, Lake County

Latitude: 38.97° N

Longitude: 122.77° W

Elevation: 1,439 (m) 4,721 (f)

Volcano type: volcanic field

Composition: basalt to rhyolite

Most recent eruption: about 10,000 years ago

Nearby towns: Clearlake, Kelseyville, Lakeport, Lucerne

Threat Potential: High*

*based on the National Volcano Early Warning System

Summary

The town of Clearlake lies within the volcanic field, as does much of the 43,000-acre freshwater lake of its namesake. The Geysers steam field, which sits at the southwest margin of the volcanic region, is host to one of the world's most productive geothermal power plants, producing enough electricity for 850,000 homes. The heat driving the geothermal system emanates from a zone of partially molten rock (magma) deep below the greater Clear Lake volcanic system. The most prominent volcanic feature is 300,000 year-old Mount Konocti, rising about 975 m (3,200 ft) above the southwestern shore of the lake. The most recent activity in the Clear Lake Volcanic Field occurred between 8,500 and 13,500 years ago as explosive maar eruptions in and along the shores of the southeastern part of the lake. Although there have been no documented eruptions within the last few thousand years, sporadic volcanic-type earthquakes do occur, and the numerous springs and volcanic gas seeps in the field point to its potential for future eruptions. Monitoring in the Clear Lake region by the USGS, and a collaborative effort with Calpine Corporation in the Geysers Steam Field, provides real-time tracking of earthquake activity. In addition, the USGS periodically analyzes volcanic gases and hot springs in the region.

News

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The Mystery of the Noon Booms Part 2

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We're ready for our closeup! Filming virtual field trip stops in the Clear Lake Volcanic Field

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Having a (volcanic) field day in California

Publications

California’s exposure to volcanic hazards

The potential for damaging earthquakes, landslides, floods, tsunamis, and wildfires is widely recognized in California. The same cannot be said for volcanic eruptions, despite the fact that they occur in the state about as frequently as the largest earthquakes on the San Andreas Fault. At least ten eruptions have taken place in the past 1,000 years, and future volcanic eruptions are inevitable.The

Authors
Margaret Mangan, Jessica Ball, Nathan Wood, Jamie L. Jones, Jeff Peters, Nina Abdollahian, Laura Dinitz, Sharon Blankenheim, Johanna Fenton, Cynthia Pridmore

2018 update to the U.S. Geological Survey national volcanic threat assessment

When erupting, all volcanoes pose a degree of risk to people and infrastructure, however, the risks are not equivalent from one volcano to another because of differences in eruptive style and geographic location. Assessing the relative threats posed by U.S. volcanoes identifies which volcanoes warrant the greatest risk-mitigation efforts by the U.S. Geological Survey and its partners. This update

Authors
John W. Ewert, Angela K. Diefenbach, David W. Ramsey

The California Volcano Observatory: Monitoring the state's restless volcanoes

Volcanic eruptions happen in the State of California about as frequently as the largest earthquakes on the San Andreas Fault Zone. At least 10 eruptions have taken place in California in the past 1,000 years—most recently at Lassen Peak in Lassen Volcanic National Park (1914 to 1917) in the northern part of the State—and future volcanic eruptions are inevitable. The U.S. Geological Survey Californ

Authors
Wendy K. Stovall, Mae Marcaida, Margaret T. Mangan

Science

Mining and mineralization of the Clear Lake region

The Geysers-Clear Lake area has been one of the most productive in the United States for mercury, and gold was mined in the late 1800s. Many of the deposits are directly associated with outcrops of early Clear Lake volcanic rocks.
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Mining and mineralization of the Clear Lake region

The Geysers-Clear Lake area has been one of the most productive in the United States for mercury, and gold was mined in the late 1800s. Many of the deposits are directly associated with outcrops of early Clear Lake volcanic rocks.
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Gas monitoring at Clear Lake Volcanic Field

The USGS periodically analyzes volcanic gases and hot springs at Clear Lake volcanic field during ground-based campaigns.
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Gas monitoring at Clear Lake Volcanic Field

The USGS periodically analyzes volcanic gases and hot springs at Clear Lake volcanic field during ground-based campaigns.
Learn More

Deformation monitoring at Clear Lake Volcanic Field

When magma moves into a volcanic system, and closer to the surface of the earth, the area surrounding the volcano may move upward and outward.
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Deformation monitoring at Clear Lake Volcanic Field

When magma moves into a volcanic system, and closer to the surface of the earth, the area surrounding the volcano may move upward and outward.
Learn More