Clear Lake lies within the Clear Lake Volcanic Field, as designated by the United States Geological Survey. The volcanic field contains The Geysers, a steam field which powers a network of the world's most productive geothermal power plants. There are numerous small faults present in the south end of the lake as well as many volcanoes, ranging in age from 10,000 to 2.1 million years, the largest being Mount Konocti, sitting at the middle of the lake's south shore. There have been no eruptions from the Clear Lake Volcanic Field for thousands of years, but there are indicators currently being monitored that suggest there is the potential for future eruptions. These indicators include volcanic-type earthquakes, hot spring activity and seepage of volcanic gas