Lassen Peak /

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 northern California to southwestern British Columbia. Located in the Shasta Cascade region of Northern California, Lassen rises 2,000 feet (600 m) above the surrounding terrain and has a volume of 0.5 cubic miles (2 km), 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 1,000 feet (300 m) higher than Lassen Peak. Lassen Peak is the only volcano in the continental United States other than Mount St. Helens to erupt during the 20th century. On May 22, 1915, a powerful explosive eruption at Lassen Peak devastated nearby areas, and it rained volcanic ash as far away as 200 miles (300 km) to the east. This explosion was the most powerful in a series of eruptions from 1914 through 1917. These were the last eruptions in the Cascade Mountains that occurred before the explosion of Mount St. Helens in the State of Washington. Lassen Volcanic National Park was created in Shasta County, Calif., to preserve the