Friday, March 27, 2009
Subscribe to:
Posts (Atom)
General Facts About the Volcano
Mt. St. Helens is a continental stratovolcano, also known as a composite volcano, located in Skamania County, Washington. Mount St. Helens is located only 53 miles northeast of Portland, Oregon and rests at a subduction boundary where the North American Plate meets the Juan de Fuca Plate. The volcano has an elevation of 8,365 feet.
May 18, 1980
On this day the the deadliest volcanic eruption in the history of the United States occurred. This eruption killed 57 people and caused millions of dollars of destruction. The eruption blew out the side of the volcano turning it into a semi-circle like crater. The eruption destroyed 230 square miles of forest and sent a cloud of ash skyward, causing many states to be covered in ash.
Eruption Style
Mount St. Helens has very explosive eruptions that are known for their pyroclastic flows, ash spread, and debris. The volcano erupts a lava with a very high viscosity. It is known as Dacite lava, this type of lava contains 65% silica causing it to be very sticky and have very explosive eruptions due to pressure build up.
Most Recent Eruption
The most recent eruption from Mount St. Helens occurred on January 16, 2008. This was a very small eruption that caused no damage.
Works Cited
"CVO Photo Archives - Mount St. Helens - Before/After Images - 1980-2004." USGS Cascades Volcano Observatory (CVO). 23 Mar. 2009 .
Glicken, Harry. After Eruption. 10 Sept. 1980. USGS.
Glicken, Harry. North Fork Toutle River valley in November 1983. 17 May 1980. USGS.
"Global Volcanism Program | St. Helens | Summary." Smithsonian Institution - Global Volcanism Program: Worldwide Holocene Volcano and Eruption Information. 23 Mar. 2009.
Lauber, Patricia. Volcano the eruption and healing of Mount St. Helens. New York: Aladdin Books, Maxwell Macmillan Canada, Maxwell Macmillan International, 1993.
MountStHelens.com Information Resource Center & Visitor Guide. 23 Mar. 2009.
Topinka, Lyn. 4 Years After Eruption. 1981. USGS.
Glicken, Harry. After Eruption. 10 Sept. 1980. USGS.
Glicken, Harry. North Fork Toutle River valley in November 1983. 17 May 1980. USGS.
"Global Volcanism Program | St. Helens | Summary." Smithsonian Institution - Global Volcanism Program: Worldwide Holocene Volcano and Eruption Information. 23 Mar. 2009
MountStHelens.com Information Resource Center & Visitor Guide. 23 Mar. 2009
Topinka, Lyn. 4 Years After Eruption. 1981. USGS.