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
