CALIFORNIA (KTXL) — It has been more than 100 years since California’s volcanoes have seen any action.
Before it became Lassen Volcanic National Park, Lassen Peak rocked Northern California with a series of eruptions between 1914 and 1921.
On May 30, 1914, a small phreatic eruption (which is when water beneath the ground or on the surface is heated by lava, magma or hot rocks) occurred at a new vent near the summit of the peak, according to the United State Geological Survey (USGS).
This would mark the beginning of more than 150 explosions of differing sizes over the next year.
In mid-May 1915, the most violent of the eruptions occurred as lava flowed about 100 meters over the west and possibly east crater walls, according to the USGS.
A large volcanic mudflow, or lahar, generated by the lava flow coming in contact with a snowfield, traveled 11 miles down Lost Creek.
A massive explosion on May 22, 1915 produced a pyroclastic flow that destroyed a nearly four-mile area from the summit and also created lahars that traveled more than 12 miles down Lost Creek.
A lobe of tephra, which is rock, ash or lava bombs from an eruption, was located nearly 19 miles northeast of Lassen Peak. Ash from the explosion was also found as far as Elko, Nevada, more than 310 miles from the eruption.
According to the National Park Service, “periodic measurements of ground deformation and volcanic gas emissions and continuous transmission of data from a local network of nine seismometers to USGS officer in Menlo Park” are being used to monitor Lassen Peak.
The USGS lists Lassen Peak as a “high to very high” threat level. It is one of five California volcanoes to erupt in the last 3,500 years.
Lassen Volcanic National Park was created to preserve the area within the area of the explosion and is one of the oldest national parks in the United States.
The park features the four “classic” types of volcanoes including; Shield, Cinder Cone, Plug Dome and Composite.