Via Discovery.com hat tip to Dave Carlson over at the ESCONI Yahoo Discussion Group
The buttes last erupted between 940 and 0 B.C., not 30,000 years ago, as previously thought, a new study detailed online Oct. 15 in the journal Geology reports. The new age — which makes these some of California's youngest volcanoes — pushes the volcanic quintuplets into active status. The California Volcano Observatory, launched in February by the U.S. Geological Survey (USGS), already lists the area as a high threat for future blasts.