| Round Mountain Volcano, California | |
| Elevation: | 2,294 |
| Last Eruption: | 8,500-10,000 years |
| Volcanic Region: | Clearlake Volcanic Field |
| Coordinates: | 39.048955°N 122.636205°W |
| Location: | Lake County, Clearlake Oaks, California, USA |
| Type: | Cinder Cone |
Round Mountain (a dormant Volcanic Cinder Cone located in the Clearlake Volcanic field) is located 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 and raised the valley level to 400 feet above Clear Lake.[1]
The Clearlake 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[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 according to "2018 Update to the U.S. Geological Survey National Volcanic Threat Assessment". 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 Geologic History of the Surrounding area including the Volcano (which is covered with heavy concentrations of chaparral similar to the European maquis shrubland. Oak, Pacific madrone, manzanita, western white pine and other plant species of the California coastal mountains that dominate the area) has been studied and documented by the USGS and prominent geologists as far back as 1938. At an approximate elevation of 2,294 feet (699 meters) the volcano exhibits a distinctive sunken concave of a cinder cone volcano.
The Dormant Round Mountain Volcano is credited with the creation of the High Valley through repeated eruptions the last of which is thought to be 8,500-10,000 years ago. The result was an elevated valley at approximately 1,600 feet in elevation with distinct ridgelines reaching up to 3,000 feet.[3]