  lassen peak, also known as mount lassen, is the southernmost active volcano in the cascade range. it is part of the cascade volcanic arc which is an arc that stretches from southwestern british columbia to northern california. located in the shasta cascade region of northern california, lassen rises  above the surrounding terrain and has a volume of , making it one of the largest lava domes on earth.  it was created on the destroyed northeastern flank of now gone mount tehama, a stratovolcano that was at least  higher than lassen peak. on may 22, 1915, a powerful explosive eruption at lassen peak devastated nearby areas, and spread volcanic ash as far as  to the east. this explosion was the most powerful in a series of eruptions from 1914 through 1917. lassen peak and mount st. helens are the only two volcanoes in the contiguous united states to erupt during the 20th century. lassen volcanic national park was created in shasta county, calif., to preserve the devastated areas a
20th-century_volcanic_events Cascade_Range Cascade_Volcanoes Cirques Lassen_Volcanic_National_Park Lava_domes Subduction_volcanoes United_States_National_Park_high_points VEI-3_volcanoes Volcanoes_of_California Volcanoes_of_Shasta_County,_California