Volcanoes Flashcards
What is an exclusion zone?
An area where people are not meant to be
Red - the most dangerous
Blue - not recommended
Why are composite volcanoes explosive?
They are acidic and viscous (forms mounds when it erupts)
High viscosity can form plugs which builds up pressure, more gas is erupted do to expansion and a more powerful explosion occurs
When was the Mount St. Helens eruption?
May 18th 1980
Why did Mount St. Helens erupt?
The Juan de Fuca plate subducts the North American
We’re exclusion zones set up in the Mount St. Helens eruption?
Yes
1000 people were evacuated
What happened to cause the explosion on Mount St. Helens?
A bulge on the volcanoes side exploded after growing 5m daily
What were the immediate effects of the Mount St. Helens explosion?
60,000 acres of trees destroyed Ash buried buildings 57 people were killed Flooding occurred from 70% of the snow and ice on top of the mountain Communication was destroyed
What were the long term effects of the Mount St. Helens explosion?
Animals that survived died of starvation Methane gas continued to be released from the volcano $1.4 million rebuilding cost Logging industry was destroyed The economy altered
When was the Montserrat volcanic eruption?
July 1995 - June 1997
Why was there a volcanic eruption in Montserrat?
The North American plate subducts the Caribbean causing an earthquake and an eruption that lasts 2 years
Were people evacuated from Montserrat?
Yes
5000 out of 12,000 inhabitants of the southern half of the island
What were the short term effects of Montserrat?
19 people died
Pyroclastic flows of 120mph covered towns in ash
Evacuation
Temporary accommodation built
British government would not send aid immediately
Traffic congestion
Unemployment 7-50%
What were the long term effects of Montserrat
An exclusion zone is still in place Building of new permanent housing in the North Re-establishment of air and sea links Moving the capital to the north of the island £11 million on a new airports Skills shortages Tourism collapse Respiratory problems
