Earthquakes and Eruptions in Eastern California
A huge volcano erupted violently about 760,000 years ago on the eastern side of the Sierra Nevada, forming a large depression called the Long Valley Caldera. This “super-eruption” was estimated to be more than 2,000 times larger than the 1980 eruption of Mt St Helens...Today, the Mammoth Lakes resort area is on the western edge of the ancient caldera.
