Clear Lake Volcano
Updated: Oct 17, 2025 13:30 GMT -
volcanic field
California, USA, 38.97°N / -122.77°W 
Summit height: 1439 m / 4,721 ft
Current status: normal or dormant (1 out of 5)
Clear Lake volcanic field lies in the northern Coast Ranges, California, ca. 135 km north of San Francisco. The volcanic field consists of lava dome complexes, cinder cones, and maars of basaltic-to-rhyolitic composition. Mount Konocti, a dacitic lava dome on the south shore of Clear Lake, is the largest volcanic feature.
The area has intense gethermal activity, caused by a large, still hot silicic magma chamber about 14 km wide and 7 km beneath the surface. It provides the heat source for the Geysers, the world's largest producing geothermal field on the SW side of the volcanic field. Its geothermal power plants can generate approximately 2000 megawatts, enough to power two cities the size of San Francisco.
The latest volcanic activity happened about 10,000 years ago and formed maars and cinder cones along the shores of Clear Lake, the larges natural freshwater lake in California. Volcanism around Clear Lake is related to the complex San Andreas transform fault system.
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Clear Lake volcano eruptions: ca. 10,000 years ago
Latest nearby earthquakes
| Date and Time | Mag / Depth | Distance / Location | |||
|---|---|---|---|---|---|
| Oct 17, 12:49 pm (Universal Time) | 1.0 2.5 km | 16 km (10.1 mi) to the S | 6 km W of Cobb, CA | Info | |
| Oct 17, 04:34 am (GMT -7) | 1.0 2.9 km | 17 km (10.9 mi) to the S | 7 km NW of the Geysers, CA | Info | |
| Oct 17, 09:35 am (Universal Time) | 1.0 1.7 km | 17 km (10.9 mi) to the S | 9 km NW of the Geysers, CA | Info | |
| Oct 17, 09:00 am (Universal Time) | 1.0 2.6 km | 17 km (10.3 mi) to the S | 7 km NW of the Geysers, CA | Info | |
| Oct 17, 12:26 am (GMT -7) | 0.5 7.3 km | 16 km (10.2 mi) to the S | 9 km NW of the Geysers, CA | Info | |
| Oct 17, 12:25 am (GMT -7) | 1.0 2 km | 16 km (10.1 mi) to the S | 8 km NW of the Geysers, CA | Info | |
| Oct 17, 05:26 am (Universal Time) | 0.6 2.2 km | 17 km (10.8 mi) to the SW | 10 km WNW of the Geysers, CA | Info | |
| Thursday, October 16, 2025 GMT (1 quake) | |||||
| Oct 16, 05:41 am (Universal Time) | 2.0 1.7 km | 17 km (10.7 mi) to the S | 4 km W of Cobb, CA | Info | |
| Wednesday, October 15, 2025 GMT (3 quakes) | |||||
| Oct 15, 04:56 am (Los Angeles) | 2.1 2.7 km | 16 km (10.2 mi) to the S | 7 km NW of the Geysers, CA | Info | |
Background
Volcanic activity has been largely non-explosive, with the exception of one major explosive eruption that must have occurred and deposited a airfall tuff. Most lavas found here range from basalt through rhyolite in composition, dacite being the most dominant type.Eruptions at Clear Lake volcanic field:
4 eruptive episodes separated by time gaps of ca. 150-200,000 years have been recognized: 2.1-1.3 million years ago (m.y.), 1.1-0.8 m.y., 0.65-0.30 m.y., and 100,000-10,000 years ago. The total volume of about 100 individual eruptions exceeds 70 cubic kilometers.
Eruptive products from the first activity episode are found in the east of the field. The second activity episode constructed Cobb Mountain (1 million years, Ma) and Mount Hannah (0.9 Ma). The third episode of activity was at the Mount Konocti–Thurston Lake area, the most voluminous dacite and rhyolite feature of the Clear Lake volcanics.
The most recent activity, up to about 10,000 years ago were small mostly basaltic and andesitic eruptions in the north of the field.
Sources: GVP, NCGS (Northern California Geological Society)
Clear Lake Volcano Photos
Clear view onto the lava lake inside Marum's west crater. (Photo: Tom Pfeiffer)
Again the Nyiragongo lava lake. The red glow of the lava was clearly visible through the day. (Photo: shinkov)
The sun is just about to rise above the horizon. The lava lake is mostly crusted over and the dry weather makes for a very clear view onto the lake. (Photo: Tom Pfeiffer)
Thanks to the risen level of the lake, the rim near the campsite now offers unobstructed, perfect views of the whole lake. And thanks to the prevailing easterly winds, it...
Latest satellite images
Clear Lake Volcano Maps
Below is a selection of maps showing the location and surroundings of the volcano at various resolutions based on aerial-imagery / terrain maps. Feel free to use them for non-commercial purposes on your blog or website as long as you credit them with a link back to this page (click to copy it).
Satellite/aerial-type map of Clear Lake volcano (world scale)
Terrain-type map of Clear Lake volcano (world scale)
Satellite/aerial-type map of Clear Lake volcano (region scale large)
Terrain-type map of Clear Lake volcano (region scale large)
Satellite/aerial-type map of Clear Lake volcano (region scale medium)
Terrain-type map of Clear Lake volcano (region scale medium)
Satellite/aerial-type map of Clear Lake volcano (region scale small)
Terrain-type map of Clear Lake volcano (region scale small)
Satellite/aerial-type map of Clear Lake volcano (local scale large)
Terrain-type map of Clear Lake volcano (local scale large)
Satellite/aerial-type map of Clear Lake volcano (local scale medium)
Terrain-type map of Clear Lake volcano (local scale medium)
Satellite/aerial-type map of Clear Lake volcano (local scale small)
Terrain-type map of Clear Lake volcano (local scale small)
Satellite/aerial-type map of Clear Lake volcano (scale of 10s of km)
Terrain-type map of Clear Lake volcano (scale of 10s of km)
Satellite/aerial-type map of Clear Lake volcano (scale of 20-40 km)
Terrain-type map of Clear Lake volcano (scale of 20-40 km)
Satellite/aerial-type map of Clear Lake volcano (scale of approx. 10-20 km)
Terrain-type map of Clear Lake volcano (scale of approx. 10-20 km)
Satellite/aerial-type map of Clear Lake volcano (scale of 5-10 km)
Satellite/aerial-type map of Clear Lake volcano (scale of few kilometers)
