MDC Volcano (Mount St Helens, USA) Flashcards Preview

Geography Case Studies > MDC Volcano (Mount St Helens, USA) > Flashcards

Flashcards in MDC Volcano (Mount St Helens, USA) Deck (21):
1

Where

Mont St Helens- Cascade Range, Washington State, North-West America

2

What plates

Joan de Fuca sinks under North American plate

3

Why was it surprising

Dormant for 400 years

4

Warning signs

Bulge appeared on North Face from blockage in Main Vent

5

When

18th May 1980 0833 hours

6

Behaviours

Blew of 390m from summit

7

Primary effects

2 million gas mask ordered
Climate change
Tourists caught in mudflow

8

When people thought it would erupt

Residents instructed to leave
No visitors within an 8km exclusion zone

9

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'

10

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

11

Sideways eruption

Blast of pulverised rock, glacier ice and ash wiped out all living things within 27km North of the crater

12

Deaths

57

13

Immediate reaction

Helicopters mobilised to search for injured

14

Problems from ash

Planes grounded
Caused power outages
Clogged air conditioning
Blocked roads

15

Ash cleared

Within 3 days (on the roads)

16

Positive impact

Ash would improve fertility of the soil

17

Within 10 years

Traces of vegetation
Insects birds and animals returned

18

Money spent on transformation

$1.4 million

19

Monument

National monument in 1982

20

Visitors now

3 million each year

21

Road to volcano

Reopened in 1990

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