California Volcanoes

 (California) has erupted, on the average, at least once per 800 years during the last 10,000 years, and about once per 600 years during the last 4,500 years. The last known eruption occurred about 200 radiocarbon years ago.
The most recent eruptive activity occurred at Lassen Peak (California) in 1914-1917 A.D.