The Cascade Range of the Pacific Northwest has more than a dozen potentially active volcanoes. Cascades volcanoes tend to erupt explosively, and on average two eruptions occur per century--the most recent were at Mount St. Helens, Washington (1980-86), and Lassen Peak, California (1914-17). To help protect the Pacific Northwest's rapidly expanding population, USGS scientists at the Cascades Volcano Observatory in Vancouver, Washington, monitor and assess the hazards posed by the region's volcanoes. -- Dzurisin, et.al., 1997 |