Restless Earth

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  • Created by: Dechante
  • Created on: 10-05-17 17:21
What is the difference between a continental crust and an oceanic crust?
Continental crust is thicker and less dense. Oceanic crust is thinner and more dense.
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What is a destructive margin?
Destructive margins are where two plates are moving towards each other. Where a oceanic plate meets a continental plate, the denser oceanic plate is forced down into the mantle and destroyed. This often creates volcanoes and ocean trenches.
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What happens when two continental plates meet at a destructive margin?
Where two continental plates meet, the plates smash together, but no crust is destroyed. This includes fold mountains.
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What is a constructive margin?
Constructive margins are where two plates are moving away from each other e.g at the mid-Atlantic ridge. Magma rises from the mantle to fill the gap and cools, creating new crust.
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What happens at the conservative margin?
Conservative margins are where two plates are moving sideways past each other, or are moving in the same direction but at different speeds e.g along the west coast of the USA. Crust isn't created or destroyed.
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How are fold mountains formed?
Fold mountains are formed when plates collide at destructive margins.
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How are fold mountains formed?
So fold mountains are found at destructive plate margins and places where there used to be destructive margins. When tectonic plates collide the sedimentary rocks that have been built up between them are folded upwards to form mountains.
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Where are fold mountains found?
You can get fold mountains where a continental plate and a oceanic plate collide (the Andes in South America). You can also get fold mountains where two continental plates collide (Himalayas in Asia).
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How are oceanic trenches formed?
When a continental plate meets with an oceanic plate a subduction zone forms. The denser oceanic plate subducts beneath the less dense continental plate forming a trench.
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What are composite volcanoes?
These are made up of ash and lava that's erupted, cooled and hardened into layers. The lava is usually thick and flows slowly. it hardens quickly to form a step sided volcano.
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What are shield volcanoes?
These are made up of only lava. The lava is runny. It flows quickly and spreads over a wide area, forming a low, flat area.
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What are dome volcanoes?
These are made up of only lava. The lava is thick. It flows slowly and hardens quickly, forming a steep-sided volcano.
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How do people use the Alps?
Farming (farm goats to pride milk, cheese and meat), Tourism (100 million tourists visit a year), Hydro-electric power (Switzerland gets 60% of electricity from the Alps), Mining (used to mine gold,silver,copper, iron ore and salt)
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How have people adapted to conditions in the Alps?
Steep relief (farmed goats because they are well adapted to live on steep mountains), Poor soils (Animals are grazed in high areas because soil isn't great for growing crops), Limited communications (roads have been built over passes)
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Soufrière Hills Volcano Information
The Soufrière Hills Volcano in Montserrat erupted on June 25th 1997. It was caused by a destructive plate margin, where the analeptic plate is being forced under the Caribbean plate. Magma rose up through weak points under the Soufrère hills.
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What are the primary impacts of the Soufrière Hills Volcano?
19 people killed, 7 injured, farmland destroyed, 2/3 homes destroyed, Large areas were covered with volcanic material
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What are secondary impacts of the Soufrière Hills Volcano?
Fires destroyed many buildings, population decline (8000 people have left since), tourists stayed way disrupting the economy, tourism is increasing as people come to see the volcano, volcanic ash has improved soil fertility.
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What was the immediate response?
People were evacuated from the south to safe areas, shelters were built to to house evacuees, temporary infrastructure was built, UK provided £17 million of emergency aid, Local emergency services provided support units to search for/rescue surviors
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What were the long-term responses?
The Montserrat Volcano Observatory has been set up to try and predict future eruptions, A risk map was created and an exclusion zone is in place, The UK has provided £41 million to develop the north of the island
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What are the characteristics of a super volcano?
The characteristics of a super volcano are is that it's flat, they cover a large area and have a caldera (unlike normal volcanoes where there's just a crater at the top)
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What are the likely effects of a super volcano?
Ash will shoot kilometres into the air and block out almost all daylight over continents, The ash will also settle over hundreds of square kilometres, a thick cloud of super heated gas and ash will flow at high speed from the volcano killing things
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Other cards in this set

Card 2

Front

What is a destructive margin?

Back

Destructive margins are where two plates are moving towards each other. Where a oceanic plate meets a continental plate, the denser oceanic plate is forced down into the mantle and destroyed. This often creates volcanoes and ocean trenches.

Card 3

Front

What happens when two continental plates meet at a destructive margin?

Back

Preview of the front of card 3

Card 4

Front

What is a constructive margin?

Back

Preview of the front of card 4

Card 5

Front

What happens at the conservative margin?

Back

Preview of the front of card 5
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