MDC Volcano (Mount St Helens, USA) Flashcards
Where
Mont St Helens- Cascade Range, Washington State, North-West America
What plates
Joan de Fuca sinks under North American plate
Why was it surprising
Dormant for 400 years
Warning signs
Bulge appeared on North Face from blockage in Main Vent
When
18th May 1980 0833 hours
Behaviours
Blew of 390m from summit
Primary effects
2 million gas mask ordered
Climate change
Tourists caught in mudflow
When people thought it would erupt
Residents instructed to leave
No visitors within an 8km exclusion zone
David Johnston quote
‘This is like standing next to a dynamite keg and the fuse is lit, but you don’t know how long the fuse is’
Scale of volcano
Caused earthquake of 5.1 on Richter scale
Caused landslide on North-East side of mountain which was the biggest landslide ever recorded
Sideways eruption
Blast of pulverised rock, glacier ice and ash wiped out all living things within 27km North of the crater
Deaths
57
Immediate reaction
Helicopters mobilised to search for injured
Problems from ash
Planes grounded
Caused power outages
Clogged air conditioning
Blocked roads
Ash cleared
Within 3 days (on the roads)