The Clear Lake Volcanic Field is a

volcanic field A volcanic field is an area of Earth's crust that is prone to localized volcanic activity. The type and number of volcanoes required to be called a "field" is not well-defined. Volcanic fields usually consist of clusters of up to 100 volcanoes ...

beside Clear Lake in

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

's northern

Coast Ranges The Pacific Coast Ranges (officially gazetted as the Pacific Mountain System in the United States) are the series of mountain ranges that stretch along the West Coast of North America from Alaska south to Northern and Central Mexico. Although th ...

. The site of late-

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...

activity, the volcanic field consists of lava domes, cinder cones, and

maars A maar is a broad, low-relief volcanic crater caused by a phreatomagmatic eruption (an explosion which occurs when groundwater comes into contact with hot lava or magma). A maar characteristically fills with water to form a relatively shallow ...

with eruptive products varying from

basalt Basalt (; ) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90 ...

to rhyolite. The site's threat level is ranked "High" at #33 in the top volcanic threats in the United States according to "2018 Update to the U.S. Geological Survey National Volcanic Threat Assessment". The last eruption being about 11,000 years ago. Cobb Mountain and

Mount Konocti Mount Konocti is a volcano in Lake County, California on the south shore of Clear Lake. At , it is the second highest peak in the Clear Lake Volcanic Field, which consists of numerous volcanic domes and cones ranging from 10,000 to 2.1 million ...

are the two highest peaks in the volcanic field, at . Retrieved 2008-08-19. and respectively. The field's magma chamber also powers a geothermal field called

The Geysers The Geysers is the world's largest geothermal field, containing a complex of 18 geothermal power plants, drawing steam from more than 350 wells, located in the Mayacamas Mountains approximately north of San Francisco, California. Geysers produce ...

, which hosts the largest complex of geothermal power plants in the world. These can generate approximately 2000 megawatts, enough to power two cities the size of

San Francisco San Francisco (; Spanish for " Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the fourth most populous in California and 17th ...

. The Clear Lake volcanics are thought to have been the heat source for the hot springs and hydrothermal activity that formed the mercury ores at the Sulphur Bank Mine, and the gold ore at the

McLaughlin Mine The Sulphur Bank Mine is located near Clearlake Oaks and Clear Lake in Lake County, California. The mine became one of the most noted mercury producers in the world. During the 150 years since the Sulphur Bank was discovered, the area has dra ...

References

External links

USGS.gov: Clear Lake Volcanic Field, California
— ''California Volcano Observatory''.
Geysers.com: The Geysers
Volcanic fields of California Landforms of Lake County, California Maars of California Natural history of the California Coast Ranges Quaternary California Quaternary volcanoes {{LakeCountyCA-geo-stub