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Videos related to Cascades Volcano Observatory.
Following unrest that began on September 23, 2004 and the steam and ash eruptions in early October, extrusion of solid magma typified the 2004-2008 eruption at Mount St. Helens. The magma is unusually gas poor and crystal rich. Several meters of pulverized, variably sintered rock commonly coat the emergent lava spines, lending them a smooth appearance.
Following unrest that began on September 23, 2004 and the steam and ash eruptions in early October, extrusion of solid magma typified the 2004-2008 eruption at Mount St. Helens. The magma is unusually gas poor and crystal rich. Several meters of pulverized, variably sintered rock commonly coat the emergent lava spines, lending them a smooth appearance.
On October 11, 2004, spines of solid, but still hot, lava punctured the surface of the deformed glacier, initiating a new dome-building phase of activity in the crater of Mount St. Helens. By late October, a larger whaleback-shaped extrusion of solid lava (called a spine) emerged from the crater floor.
On October 11, 2004, spines of solid, but still hot, lava punctured the surface of the deformed glacier, initiating a new dome-building phase of activity in the crater of Mount St. Helens. By late October, a larger whaleback-shaped extrusion of solid lava (called a spine) emerged from the crater floor.
After two weeks of increasing seismicity, Mount St. Helens began erupting on October 1, 2004. The first of several explosions shot a plume of volcanic ash and gases into the atmosphere. Four additional steam and ash explosions occurred through October 5, and three produced noticeable fallout of fine ash downwind.
After two weeks of increasing seismicity, Mount St. Helens began erupting on October 1, 2004. The first of several explosions shot a plume of volcanic ash and gases into the atmosphere. Four additional steam and ash explosions occurred through October 5, and three produced noticeable fallout of fine ash downwind.
On October 1, 2004, an explosion in the crater of Mount St. Helens sent ash and water vapor several thousand feet into the air. It was the dramatic beginning of an eruption that continued for the next 3+ years. The explosion fractured Crater Glacier and hurled rocks for at least one-half mile across the western half of the glacier and the 1980-1986 lava dome.
On October 1, 2004, an explosion in the crater of Mount St. Helens sent ash and water vapor several thousand feet into the air. It was the dramatic beginning of an eruption that continued for the next 3+ years. The explosion fractured Crater Glacier and hurled rocks for at least one-half mile across the western half of the glacier and the 1980-1986 lava dome.
USGS scientists C. Dan Miller, Don Mullineaux, Mike Doukas, Norm Banks, Don Swanson, and Richard Waitt talk about their experiences at Mount St.
USGS scientists C. Dan Miller, Don Mullineaux, Mike Doukas, Norm Banks, Don Swanson, and Richard Waitt talk about their experiences at Mount St.
Mount St. Helens erupted catastrophically on May 18, 1980 beginning at 8:32 a.m. USGS geologist Don Swanson photographed and filmed the eruption from about 9:30 a.m. to 12:30 p.m., documenting the rising ash column and ground-hugging pyroclastic density currents.
Mount St. Helens erupted catastrophically on May 18, 1980 beginning at 8:32 a.m. USGS geologist Don Swanson photographed and filmed the eruption from about 9:30 a.m. to 12:30 p.m., documenting the rising ash column and ground-hugging pyroclastic density currents.
Eruptive activity at Mount St. Helens captured the world’s attention on May 18, 1980 when the largest historical landslide on Earth and a powerful explosion reshaped the volcano. A volcanic ash cloud spread across the US in 3 days, and encircled the Earth in 15 days.
Eruptive activity at Mount St. Helens captured the world’s attention on May 18, 1980 when the largest historical landslide on Earth and a powerful explosion reshaped the volcano. A volcanic ash cloud spread across the US in 3 days, and encircled the Earth in 15 days.