| Round Mountain | |
|---|---|
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| Highest point | |
| Elevation | 2,294 ft (699 m) |
| Coordinates | 39°02′56″N 122°38′10″W / 39.048955°N 122.636205°W |
| Geography | |
 | |
| Location | Lake County, Clearlake Oaks, California, USA |
| Geology | |
| Mountain type | Cinder cone |
| Volcanic field | Clear Lake Volcanic Field |
| Last eruption | 8,500–10,000 years ago |
Round Mountain is a dormant volcanic cinder cone located in the Clear Lake Volcanic Field in the eastern end of the High Valley. It last erupted approximately 8,500–10,000 years ago and filled the valley with volcanic debris, raising the valley level to 400 feet above Clear Lake.[1]
The Clear Lake Volcanic Field is the site of Late Pliocene to early Holocene activity and consists of lava domes, cinder cones, and maars[2] 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 in 2018 Update to the United States Geological Survey National Volcanic Threat Assessment. Cobb Mountain and Mount Konocti are the two highest peaks in the volcanic field, at 4,724 ft (1,440 m) and 4,285 ft (1,306 m) respectively.
- ^ Sutton, Nancy (July 1, 2005). "Establishment of the High Valley Viticultural Area (2003R-361P)". Federal Register.
- ^ Ball, Jessica (September 1, 2022). "Stratigraphy and eruption history of maars in the Clear Lake Volcanic Field, California". Frontiers in Earth Science. 10. doi:10.3389/feart.2022.911129.