The 2004–2008 volcanic activity of Mount St. Helens has been documented as a continuous eruption with a gradual extrusion of magma at the Mount St. Helens volcano in Washington, United States. Starting in October 2004 and ceasing in January 2008, there was a gradual building of a new lava dome. The new dome did not rise above the caldera created by the 1980 eruption of Mount St. Helens.
On September 23, 2004, around 2:00 a.m. PDT, Mount St. Helen...
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The 2004–2008 volcanic activity of Mount St. Helens has been documented as a continuous eruption with a gradual extrusion of magma at the Mount St. Helens volcano in Washington, United States. Starting in October 2004 and ceasing in January 2008, there was a gradual building of a new lava dome. The new dome did not rise above the caldera 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 lava dome. Activity increased, and on September 26, the U.S. Geological Survey (USGS) and Pacific Northwest Seismograph Network issued a "notice of volcanic unrest", stating that a "hazardous event" was possible, and the U.S. Forest Service closed the mountain to all climbing. They also closed some trails in the area because of the risk of debris flows from the possible melting of the Crater...
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