Plate Tectonics Case Studies-Mount St Helens Flashcards
Where
Washington, USA, Cascade Mountains
What
Volcanic eruption, pyroclastic flows, Lahars and floods
When?
18th May 1980
Signs in march, small earthquakes, bulge on side, ash/steam released
Why
Destructive plate boundary, Juan de Fuca plate under North American plate
Type
Composite
Impacts
Cost of $1.1 billion.
200 homes destroyed
1000 flights cancelled
Airports closed 2 weeks
Impacts
57 killed,
Timber industry suffered
Unemployment
Hundreds lost homes
Impacts
27 bridges, 24km railway, 300km road destroyed
31 ships stranded-mudflows
Responses
Face masks, reduced ash intake
Emergency shelters
Ash cleanup organisations
Responses
More trees replanted, 18.4 million over 45,500 acres
Shipping channels cleared
Water monitored