• Lassen Peak from Hat Creek

    Lassen Volcanic

    National Park California

There are park alerts in effect.
show Alerts »
  • Warner Valley Road Work

    There will be paving work on the road connecting Chester to the Warner Valley beginning Monday July 21 or Tuesday July 22 and continuing through July. There may be a 30 min. delay for visitors travelling to Warner Valley and Drakesbad.

Volcanoes / Lava Flows

Nature and Science

Lassen Peak in mild eruption, 1915

(B. F. Loomis)

Every rock at Lassen originates from volcanoes. Lassen's volcanic domes are part of the most recently active Lassen Volcanic Center, which began to erupt about 825,000 years ago. Represented in the park are all four types of volcanoes found in the world--shield, composite, cinder cone, and plug dome. Unlike other Cascade volcanoes, Lassen's large plug dome and composite volcanoes are in close proximity to the smaller cinder cone volcanoes that surround the volcanic center.

The greater Lassen area has been volcanically active for about three millions years. Recently the region has seen eruptions from Cinder Cone (~350 years ago) and Lassen Peak (~100 years ago). While the area sleeps now, steam vents, boiling springs, and bubbling mudpots remain active--direct evidence that the volcanic center still smolders. No one can say when or where the next eruption will occur. We can only say that it will.


New! Recent Volcanic Activity
A series of earthquakes occured approximately 40 miles southeast of Lassen Volcanic National Park on May 24, 2013. Volcanic activity is not expected as a result of the earthquakes, although changes may occur in hydrothermal areas for a few days following the nearby earthquakes.

The volcanoes of Lassen The volcanoes in Lassen Volcanic National Park are monitored by the United States Geological Survey (USGS). Seismic stations located throughout the park allow scientists to measure earthquakes in real-time. A new exhibit in the Loomis Museum includes an interactive map displaying sesimic stations and recent earthquakes within the park. This same map is visible online as part of the California Volcano Observatory.

USGS measures seismic stations in active areas worldwide with the goal of predicting hazardous conditions. Worldwide earthquake activity, including the recent Lake Almanor earthquakes, can be viewed on the USGS website.

Map of earthquake activity near Lake Almanor
United States Geologic Survey earthquake map

Studying and Monitoring Volcanic Activity
Scientists from United States Geological Survey (USGS) study volcanic activity at Lassen Volcanic National Park as a part of the USGS Volcano Hazards Program, California Volcano Observatory (CalVO). CalVO aims to advance scientific understanding of volcanic processes and lessen the harmful impacts of volcanic activity in the volcanically active areas of California and Nevada. Select a link below to learn more.

Lassen Volcanic Interactive Monitoring Map
View real-time data on seismic stations and park earthquakes

"Hot Water" in Lassen Volcanic National Park
Fumaroles, Steaming Ground, and Boiling Mudpots (pdf, 2.4 MB)

Eruptions of Lassen Peak
California, 1914-1917 (pdf, 588 KB)

How Old is "Cinder Cone"?
Solving a Mystery in Lassen Volcanic Park, California (pdf, 3.2 MB)

Lahar Hazard Zones for Eruption-Generated Lahars
in the Lassen Volcanic Center, California (pdf, 5.8 MB)

Volcano Hazards Assessment for the Lassen Region
Northern California (pdf, 27.7 MB)

Eruption Probabilities for the Lassen Volcanic Center
and Regional Volcanism Northern California, and Probabilities for Large Explosive Eruptions in the Cascade Range web (pdf, 1.1 MB)

Did You Know?

reddish color microscopic snow alage

The reddish color sometimes observed on top of snow at Lassen Volcanic NP snow is a living organism called snow algae. When snow begins to thaw, these microscopic organisms spring to life. They function as a primary food source and are being studied for their cancer-fighting properties.