Mt St Helens Flashcards

1
Q

When was the eruption

A

18 May 1980

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2
Q

Where is Mt St Helens

A

In the South of the state of Washington

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3
Q

How many deaths

A

57

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4
Q

Height before eruption

A

9,677 feet

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5
Q

Height after eruption

A

8,363 feet

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6
Q

When did the volcano go dormant

A

1850

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7
Q

What economic activity was the most prevalent on the volcano

A

Logging

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8
Q

When did the volcano become slowly active

A

January 1980

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9
Q

What showed the growing pressure in the volcano

A

Bulge growing on North side due to magma rising from a fault

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10
Q

What was the impact of this growing threat on scientists and tourists

A

Scientists became highly concerned yet tourists were attracted

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11
Q

When was a state of emergency declared and why

A

3 April 1980

To keep the tourists away from the volcano

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12
Q

Who was allowed in the Red Zone

A

Law enforcement and scientists

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13
Q

Who was allowed in the wider Blue Zone

A

Loggers

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14
Q

Why was there anger around the danger zones

A

Some wanted stronger action (loggers wanting security and safety when working)

Some wanted less harsh restrictions (wanting to return home)

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15
Q

Magnitude of earthquake that triggered the eruption

A

5.1

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16
Q

What did the earthquake cause

A

Entire north side of the volcano slipped in the largest landslide in recorded history

17
Q

How fast did the landslide travel

18
Q

VEI

19
Q

How much sulphur dioxide was released

A

1.5 million tonnes

20
Q

Category

21
Q

Why was the affected area so much larger than predicted

A

The eruption was a lateral blast, so covered a huge amount of land to the north, rather than the predicted small area around the whole volcano

22
Q

How much land did the pyroclastic flow destroy

23
Q

How far away were some trees burned

24
Q

What did airborne ash particles cause

A

Lightning, which triggered many forest fires

25
How high were the ash clouds
23km
26
Impacts of ash in the air
Pollution of water supplies Killing livestock Restricting air traffic
27
What did ash settling on glaciers cause
It liquefied them, causing jökulhaups to destroy property and many bridges
28
What happened with the jökulhaups?
They travelled 27km into the Columbia River 3,000,000m³ of material was transported They blocked many rivers and damaged aquatic habitats
29
What was destroyed
200 homes 47 bridges 185 miles of road 15 miles of railway Many forests
30
Recovery within a year
Many of the bridges and roads rebuilt 900,000 tonnes of ash removed from roads Routes into other areas reestablished Logging restarted
31
What happened in 1980 - 1986
Numerous smaller eruptions
32
What happened in the early 2000s
Lots of activity, with eruptions of steam and ash, as well as new lava domes forming in the crater of the volcano
33
How did scientists use the event
To research how plants and animals could recover after a disaster such as this