St. Helens Volcano

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St. Helens Volcano

• Washington, USA.
• May 1980

Samantha, Jennifer Bryan
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Classification Category Geological
Hazard Date/Place Washington, DC, USA. May 18th,
1980 Population 4 132 353 Killed 57 people
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Consequences

• Flattened 570 square km of forest land
• 300,000 two bedroom homes gone
• Snapped 6000 tress.
• Caused glaciers to melt creating mudslides and
  flooding
• 46 billion gallons of water slid down the
  mountain
• Ash covered sky and went 80 000 feet in the sky
• The eruption killed 7000 large animals and
  hundreds of thousands small animals
• Caused billions of dollars in damage
• Destroyed 27 bridges

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Natural hazards faced

• The eruption caused or can cause
• Mudslides
• Mudflow
• Earthquakes
• Flooding
• Contaminated lakes
• Ruined shipping channels in
• Columbia River

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• Frequency
• St. Helens Volcano has volcanic activity every
  hundred years but is 40, 000 years old
• Duration
• The volcanic activity happened in early May
• The eruption happed May 18, all day
• Extent
• The eruption affected Washington and Columbia
• The lava damaged up to 600 square kilometers
  around the volcano.

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• Speed of onset
• Volcano was expected to erupt sometime in the
  1980s
• Until occurring earthquakes that hit in early
  May. Then St. Helens eruption happened quite
  quickly but with lots of time to prepare
• Spatial Dispersion
• The area around the volcano is likely to be
  affected
• Southern Seattle and Washington were affected the
  most being the closest to the volcano

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• Temporal Spacing
• Even though the volcano is considered young (40
  000 years old) St. Helens erupts almost every
  hundred years but recently it has been very
  active
• It was a random eruption on May 18, 1980