Mount St Helens - Case Study of a Volcano in an MEDC

Below is an amazing video made by one of the pupils from my previous school about this awesome eruption. I have checked with her and she is happy for me to show it off, the music in case you're wondering is called 'Requiem for a dream' by Clint Marshall and is from the film with the same title. Enjoy!!



Where is Mount St Helens
Mount St Helens is a volcano in the Cascades Mountain Range in Washington State in the USA.

Why is there a volcano at Mount St Helens
Mount St Helens sits on a destructive plate boundary. The oceanic Juan de Fuca plate is subducted beneath the less dense contintenal North American plate. As the Juan de Fuca plate is subducted it takes down with it ocean sediments and water which makes this volcano more explosive when it erupts. The Juan de Fuca plates melts due to the heat of the mantle and friction with the North American plate. The melting crust is less dense than the surrounding material and rises upwards into the magma chamber of Mount St Helens ready for an eruption.

What Happened?
8.32am on 18th May 1980 a 5.1 earthquake shook loose the northern flank of the volcano and the eruption began.
What were the effects? -(more specific facts can be found on the powerpoint and video)
Pyroclastic flow, lahars, dust and ash.
63 people killed.
All vegetation 21km north of the volcano was levelled.
Farming, fishing and logging industries destroyed.
Road and railway bridges on the Columbia River were washed away.
Spirit Lake was completely filled in.
What were the responses? - (see powerpoint and video)
Exclusion zone set up around the volcano
Aiports closed to prevent planes flying into the ash clouds and crashing
Volcano continues to be monitored
State of emergency declared

Mount St Helens New Ppt