Mount St Helens ( USA ) Flashcards
When was the eruption?
18th May 1980
What was happening in the build up to the earthquake?
Thousands of small earthquakes and steam explosions
What type of plate boundary is mount St Helens on?
Destructive
How much of the mountains height was removed by the eruption?
The mountain went from 2950m to 2560
What did the eruption trigger?
The largest landslide in history ( recorded )
What happened to all plant and animal life within a 25km radius of the volcano?
It was all killed or destroyed, and many rivers were clogged by mudflows and landslides
How many died to mudflows, being crushed to death or poisonous gases?
61
How many were initially rescued?
198
What did ash clouds result in?
All local flights being cancelled
How much damage in $ did Ash cause to farm machinery and crops?
$100 million
How was the eruption ( roughly ) predicted?
- measuring the frequency of earthquakes
- greater frequency and closer to the volcano indicates magma build up in the vent
- Cone size also indicates magma build up
- Scientists can also check for gas emissions ( such as sulphur dioxide ) and thermal
activity near the crater
What was the first immediate response?
Helicopters were dispatched to search and rescue those who were trapped in cars or homes etc
What happened to people in the immediate vicinity?
They were all killed however some who were caught in mudflows survived
How quickly were roads cleared?
Within 3 days to make way for aid and those stranded due to road blockages
What did president Carter promise to send due to the health risks of ash?
2 million face masks
