Mt St. Helens eruption Flashcards
Intro
Good Morning America, you are watching Ticking News, Sophia Mogre reporting live here at what is left of the remains of a small town Washington State after Mt. St. Helens, the steep-sided and explosive composite volcano, had erupted earlier last week on the 18th May 1980 at 8:23am surprising many. This (no longer dominant) volcano erupted in the West Coast of the USA in Washington State in the Cascade Mountain Range and was believed to be part of the many volcanoes located in the Ring of Fire. Prior to eruption Mt St Helens had been dominant and not erupted for over 123years.
What boundary?
Destructive boundary- 2 plates move toward each other due to the convection currents in the mantle forcing the magma up through a crack in the crust. The Oceanic Plate (Juan de Fuca- being denser) sunk beneath the continental plate (North American Plates) into the subduction zone.
Triggers that lead to the eruption:
- The excess magma rising to the surface then caused a 5.1 earth quake trigger, triggering the eruption.
- 10 000 earthquakes between March and 18th May
How it moved?
A crypto dome appeared on the side of the volcano- noting happened but it kept on growing. After a colossal explosion deep inside the volcano, lava poured out of the crater and began to flow down the side of the secondary cone, blowing the whole side of the mountain off. Many believe it was not the lava’s thrust that caused the side of the volcano to go off, but a vent inside of the volcano that was blocked.
Social effects:
- Deaths eg. Harry Truman - last words “VANCOUVER VANCOUVER THIS IS IT!”
- Suffocating
- Burnt and tight skin
- Singed hair, eyelashes and eyebrows.
- Ear pops
- Difficuty breathing
- Trapped
- 57 killed
- Submerged under water
Environmental effects:
Revise tmrw
Economic Effects:
- Cars abandoned and damaged by ash
- Timber worth $400 000 000 damaged/destroyed
- Houses and Buildings lost
- Damage to drops = $175million
Interview w survivor
Kathy Anderson - logging company (luck to survive - moved location)
^Explain at end^
Survivor = anonymous
- 1-7 on what happened
Short Term response
- 150ppl rescued in 36h
- 20mile exclusion zone
- Federal emergency help
- Evacuations (carried out)
Helicopter evacuation - Evacuees taken to school halls/churches
- Warnings
- Shovel off roof to keep house from collapsing
Long term response:
- Reboosting tourist industry
- Rebuilt roads, houses and businesses
- Satellite warning system
Most useful monitoring of volcano
From heat seeking cameras to tilt meters and a warning system, in my opinion the top four most useful are organised emergency supplies, the spider, training the emergency services and a warning system. This is because.. But overall the best way of monitoring a volcano is the spider as before the other methods would come in handy, knowing an eruption is about to occur etc.
