5-554: The Clear Lake Volcanic Field is a volcanic field beside Clear Lake in California 's northern Coast Ranges . The site of late- Pliocene to early Holocene activity, the volcanic field consists of lava domes , cinder cones , and maars with eruptive products varying from basalt 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
10-485: 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 such as cinder cones . Lava flows may also occur. They may occur as a monogenetic volcanic field or a polygenetic volcanic field . Alexander von Humboldt observed in 1823 that geologically young volcanoes are not distributed uniformly across
15-415: The U.S. Geological Survey National Volcanic Threat Assessment ". The last eruption was about 11,000 years ago. Cobb Mountain and Mount Konocti are the two highest peaks in the volcanic field, at 4,724 feet (1,440 m) and 4,285 feet (1,306 m) respectively. The field's magma chamber also powers a geothermal field called The Geysers , which hosts the largest complex of geothermal power plants in
20-487: The Earth's surface, but tend to be clustered into specific regions. Young volcanoes are rarely found within cratons , but are characteristic of subduction zones, rift zones , or in ocean basins. Intraplate volcanoes are clustered along hotspot traces. Within regions of volcanic activity, volcanic fields are clusters of volcanoes that share a common magma source. Unlike a large volcano with satellite or subsidiary vents,
25-634: The world. These can generate approximately 2000 megawatts, enough to power two cities the size of San Francisco . 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 . This Lake County, California –related article is a stub . You can help Misplaced Pages by expanding it . Volcanic field A volcanic field or crater row
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