https://volcanoes.usgs.gov/volcanoes/mount_shasta/ Mt. Shasta Mount Shasta and Vicinity Mount Shasta and Vicinity Mount Shasta every 600 years or so Mount Shasta and Vicinity Shasta Mount Shasta and Vicinity Mount Shasta and Vicinity Shasta Mount Shasta and Vicinity California Volcano Observatory—Mount Shasta Mt Shasta Volcano Mount Shasta Mount Shasta and Vicinity usgs.gov at least 70 times Mt. Shasta Mount Shasta volcanoes.usgs.gov Mount Shasta volcanoes.usgs.gov