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Flashcards in Volcanoes Deck (15)
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1
Q

What is a volcano

A

When molten rock escapes onto the earth’s surface

2
Q

Composite volcano

A
  • Conduit system carries lava
  • Lava can break through the walls/fissures

↳ can grow to 1000s of metres high

  • Explode violently
3
Q

Shield volcano

A
  • Looks like a shield from above (large+wide)
  • Lava is thin and travels far
  • Not violent but many explosions
4
Q

Caldera volcano

A
  • Top of last volcano was blown off
  • Huge mamga chamber
  • Destructive margin volcano

↳ oceanic under continental

5
Q

What happens when a volcano erupts?

A

Magma rises (in magma chamber) → main vent/secondary cone → out of crater → smoke, ash and dust

crater + blocked with cooled magma = lava bomb

6
Q

Why does a volcano erupt?

A
  • HIgh pressure
  • Weaknesses in rock
7
Q

How can you monitor a volcano?

A
  • Digital cameras → photograph safely
  • Robot ‘spiders’ → instead of humans
  • Satellite images → change in temperature
8
Q

How can you predict a volcano’s eruption?

A
  • Seismometers → magma rising, sulphur levels
  • Lasers → detect swelling in volcano
  • Ultra sound → low frequency waves in magma

↳ gas + molten rock surge

9
Q

Dangers of a volcano

A
  • Ash fall → very fine, suspends ⇒suffocation
  • Pyroclastic falls → hot, solid material
  • Mudflow (lahars) → mix of ash + water ⇒ washes things away
10
Q

Advantages of a volcano

A
  • Rich, thick soil → fertile, ⇒ high crop yield
  • Attracts tourists → creates jobs ⇒ employment, wealth
  • Heat → source of energy
11
Q

Location and date of volcano

A
  • Mount St. Helens (MEDC)
  • 20th March 1980
  • America, North State
12
Q

Causes of volcano

A
  • 2 plates colliding to form a destructuve margin

↳ Juna de Fuca and North American Plate

13
Q

Effects of volcano

A
  • Around 57 deaths
  • Dozen bridges destroyed
  • Covered 2302 miles
  • Many trees uprooted and washed down river
  • Earthquakes
14
Q

Short term responses for volcano

A
  • 24 hour aerial surveillance
  • Helicopter search and rescue
  • Masks
  • Emergency treatment
  • Ash cleared from roads
15
Q

Long term responses for volcano

A
  • Trees replanted
  • Buildings and roads rebuilt
  • Drainage recovered