Transcript Mount St. Helens

Mount St. Helens
By Maha, Camille, and Esther
Type of Volcano
Mount St. Helens is an active stratovolcano
(composite volcano).
Geographic Location
Mount St. Helens
Latitude and Longitude:
46.2000° N, 122.1892° W
Nearest Major City
•
Nearest City: Vancouver, Washington
•
Population: 161,791
•
Distance from Volcano: 47 miles
Eruptions
• Most Recent Eruption: 2004 – July 10, 2008
• Most Destructive Eruption: May 18, 1980
Other Events Associated with
Eruption
• In 1980 there was an Earthquake with the magnitude of 5.1 a
mile below the volcano, which set the volcano off
• Also during the 1980 eruption an avalanche was caused
which would be recorded as the largest landslide debris
avalanche in historic time
Tectonic Plates
Formation of Volcano
New crust is continually being pushed away from divergent boundaries (where sea-floor
spreading occurs), increasing Earth's surface. But the Earth isn't getting any bigger. What
happens, then, to keep the Earth the same size? The answer is subduction.
In locations around the world, ocean crust subducts, or slides under, other pieces of Earth's
crust. The boundary where the two plates meet is called a convergent boundary. Deep
trenches appear at these boundaries, caused by the oceanic plate bending downward into
the Earth.
Deep below the Earth's surface, subduction causes partial melting of both the ocean crust
and mantle as they slide past one another. This melting generates magma that makes its way
to the surface, producing volcanoes, such as Mt. St. Helens. Most of the subducting plate
continues into the mantle, perhaps to reappear much later at a distant divergent boundary.
Other Interesting Facts
• During the past 4,000 years Mount St. Helens has erupted
more frequently than any other volcano
• Mount St. Helens erupted continuously from 2004-2008
• Mount St. Helens is 8,364 ft. but used to be 9,677 ft.
• Mount St. Helens was named after a British soldier
• On May 18,1980 a vertical plume of ash rose over 80,000 ft.
Picture URLs
Tile Page: http://en.wikipedia.org/wiki/Mount_St._Helens
Type of Volcano: http://entequilaesverdad.blogspot.com/2010/05/happy-30th-anniversary-mountsaint.html
Geographic Location: http://webspace.ship.edu/cjwolt/geology/cas.htm
Nearest Major City: http://en.wikipedia.org/wiki/Mount_St._Helens
Eruptions: http://www.boston.com/bigpicture/2010/05/mount_st_helens_30_years_ago.html
Other Events: http://www.worldtravelattractions.com/mount-saint-helens-eruptions/
Formation: http://www.pbs.org/wgbh/aso/tryit/tectonics/convergent.html
Facts: http://en.wikipedia.org/wiki/1980_eruption_of_Mount_St._Helens