The Clear Lake Volcanic Field is a

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

beside Clear Lake in

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

's northern Coast Ranges. The site of late-

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Holocene The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...

activity, the volcanic field consists of

lava dome In volcanology, a lava dome is a circular, mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions ...

cinder cone A cinder cone or scoria cone is a steep, volcanic cone, conical landform of loose pyroclastic rock, pyroclastic fragments, such as volcanic ash, clinkers, or scoria that has been built around a volcanic vent. The pyroclastic fragments are forme ...

s, and maars with eruptive products varying from

basalt Basalt (; ) is an aphanite, 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 planetary surface, surface of a terrestrial ...

rhyolite Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture (geology), texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained matri ...

. 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 was about 11,000 years ago. Cobb Mountain and

Mount Konocti Mount Konocti is a volcano in Lake County, California, Lake County, California on the south shore of Clear Lake (California), Clear Lake. At , it is the second highest peak in the Clear Lake Volcanic Field, which consists of numerous volcanic d ...

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 produced ...

, which hosts the largest complex of

geothermal power Geothermal power is electricity generation, electrical power generated from geothermal energy. Technologies in use include dry steam power stations, flash steam power stations and binary cycle power stations. Geothermal electricity generation i ...

plants in the world. These can generate approximately 2000 megawatts, enough to power two cities the size of

San Francisco San Francisco, officially the City and County of San Francisco, is a commercial, Financial District, San Francisco, financial, and Culture of San Francisco, cultural center of Northern California. With a population of 827,526 residents as of ...

. 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.

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

See also

References

External links