when was the last time mt lassen erupted
Lassen Peak On May 22, 1915, a powerful explosive eruption at Lassen Peak devastated nearby areas, and spread volcanic ash as far as 200 mi (300 km) to the east.[4] This explosion was the most powerful in a series of eruptions from 1914 through 1917. Lassen Peak and Mount St. Helens were the only two volcanoes in the contiguous United States to erupt during the 20th century.[5] Lassen Volcanic National Park was created in Tehama County, California, to preserve the devastated areas as they were, for future observation and study, and to preserve the nearby volcanic features.
Mount Rainier The most recent recorded volcanic eruption was between 1820 and 1854, but many eyewitnesses reported eruptive activity in 1858, 1870, 1879, 1882 and 1894 as well.[38]