Lassen Volcanic Center
Find U.S. Volcano
Lassen Volcanic Center has experienced hundreds of eruptions scattered over about 500 km2 (200 mi2) during the last 825,000 years. The most recent three notable eruptions were: Chaos Crags (1,100 years ago), Cinder Cone (1666 A.D.), and Lassen Peak (A.D. 1914 to 1917). The region hosts a vigorous geothermal system, numerous hot springs, steam vents, and boiling mud pots.
Quick Facts
Location: California, Shasta County
Latitude: 40.492° N
Longitude: 121.508° W
Elevation: 3,187 (m) 10,456 (f)
Volcano type: dome field, volcanic field
Composition: andesite, dacite
Most recent eruption: 1914-1917
Nearby towns: Mineral, Viola
Threat Potential: Very High*
*based on the National Volcano Early Warning System
Summary
Lassen Volcanic Center lies in Lassen Volcanic National Park 88 km (55 mi) east of Redding. The park draws over 350,000 visitors each year with its spectacular volcanic landscapes.
Within the last 825,000 years, hundreds of explosive eruptions came from vents scattered over 500 km2(approximately 200 mi2). Surrounding Lassen Volcanic Center, over fifty effusive (non-explosive) eruptions have occurred in the last 100,000 years. The area has been relatively quiet for the last 25,000 years with three notable exceptions—the Chaos Crags eruption (1,100 years ago), the eruption of Cinder Cone (1666 A.D.), and the Lassen Peak eruption (A.D. 1914 to 1917).
The Lassen Peak eruption consisted mostly of sporadic steam blasts. In May of 1915, however, partially molten rock oozing from the vent began building a precarious lava dome. The dome collapsed on May 19 sending an avalanche of hot rock down the north flank of the volcano. Three days later, a vertical column of ash exploded from the vent reaching altitudes of 30,000 feet. The ash column spawned a high-speed ground flow of hot gas and fragmented lava. Ash from the top of the column drifted downwind 200 miles to the east, as far as Winnemucca, NV. On both days, melting snow fueled mudflows, flooding drainages 20-30 miles away. The older Chaos Crags eruption was similar in style but considerably larger in magnitude.
Volcanic earthquakes are common at Lassen, although most are too small to be felt. Non-volcanic earthquakes along regional faults also occur—earthquake swarms in 1936, 1945-1947, and 1950 included several events above magnitude 4.0, with the two largest registering 5.0 and 5.5. Ground surveys show localized subsidence of the volcano, probably due to motion on regional faults.
News
A brief history of the Lassen Volcano Observatory (1926-1935)
Recent large earthquakes near Lassen are just another day in the Basin and Range
Altered states (of volcanic rock)
Publications
California’s exposure to volcanic hazards
The potential for damaging earthquakes, landslides, floods, tsunamis, and wildfires is widely recognized in California. The same cannot be said for volcanic eruptions, despite the fact that they occur in the state about as frequently as the largest earthquakes on the San Andreas Fault. At least ten eruptions have taken place in the past 1,000 years, and future volcanic eruptions are inevitable.The
2018 update to the U.S. Geological Survey national volcanic threat assessment
When erupting, all volcanoes pose a degree of risk to people and infrastructure, however, the risks are not equivalent from one volcano to another because of differences in eruptive style and geographic location. Assessing the relative threats posed by U.S. volcanoes identifies which volcanoes warrant the greatest risk-mitigation efforts by the U.S. Geological Survey and its partners. This update
The California Volcano Observatory: Monitoring the state's restless volcanoes
Volcanic eruptions happen in the State of California about as frequently as the largest earthquakes on the San Andreas Fault Zone. At least 10 eruptions have taken place in California in the past 1,000 years—most recently at Lassen Peak in Lassen Volcanic National Park (1914 to 1917) in the northern part of the State—and future volcanic eruptions are inevitable. The U.S. Geological Survey Californ
