When was the last major volcanic activity at Mount St Helens, Washington USA?
2004–08 volcanic activity of Mount St. Helens 2004–08 volcanic activity of Mount St. Helens The 2004–2008 volcanic activity of Mount St. Helens, Washington, United States has been documented as a continuous eruption in the form of gradual extrusion of magma. Starting in October 2004 and ceasing in January 2008, a new lava dome was built up. The new dome did not rise above the crater created by the 1980 eruption of Mount St. Helens. On September 23, 2004, around 2:00 a.m. PDT, Mount St. Helens experienced an earthquake swarm, with about 200 small (less than magnitude 1) earthquakes occurring less than one-half mile (one kilometer) below the
Mount St. Helens National Volcanic Monument Mount St. Helens National Volcanic Monument Mount St. Helens National Volcanic Monument is a U.S. National Monument that includes the area around Mount St. Helens in Washington. It was established on August 27, 1982 by U.S. President Ronald Reagan following the 1980 eruption. The 110,000 acre (445 km) National Volcanic Monument was set aside for research, recreation, and education. Inside the Monument, the environment is left to respond naturally to the disturbance. Mount St. Helens National Volcanic Monument was the United States' first such monument managed by the U.S. Forest Service. At dedication ceremonies on May 18, 1983, Max Peterson,