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Geography (Why do Plates Move? (Landforms (Rift valleys are created as the…
Geography
Why do Plates Move?
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This energy keeps the mantle in a liquid, molten state.
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Landforms
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Mountain ridges are created along the boundary 2-3km high where the rock is heated and thermally expands.
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Earthquakes
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Tectonic earthquakes occur at every type of plate boundary. The energy is built up here because of the stress caused by mantle currents on plate edges.
Isostatic earthquakes occur where the solid earth's crust has been split by a fault. When the earth's crust rises and falls stress builds up along these faults and when it is released earthquakes occur.
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The Richter Scale
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3-4 : Felt by many people, hanging things may swing.
6-7 : Pipes may break, some buildings may collapse.
2-3 : Felt by few people, comparable to the vibrations of a passing lorry.
7-8 : Bridges broken, few structures left standing
1-2 : Not felt by people, only detectable by a seismometer.
8-9 : Near total destruction, waves moving through the earth visible to the naked eye.
The Earth's Structure 
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Tectonic/Volcanic Areas
Benefits
Mining. Valuable materials are often found in volcanoes. People mine them despite the danger of eruption and fumes. They often cannot afford the correct protective clothing but take any work they can get.
Tourism. Millions of people visit volcanoes all over the world every year for the thrill and danger. This boosts the revenue that the local communities generate, therefore benefiting the country and its residents.
Farming. Lava and ash kill livestock and destroy crops. However, after thousands of years, the weathering of the lava produces extremely fertile soil.
Family, Friends and Feelings. People may often not want to leave these sometimes dangerous areas because of family and friends, but also because they are in denial that disasters like earthquakes or eruptions may occur.
Geothermal Energy. In volcanically active areas, steam is heated by hot magma in permeable rock, then boreholes are drilled into the rock to harness the superheated steam to drive the turbines of a power station. About 30% of Iceland's electricity is generated by geothermal energy power plants.
Aseismic Design
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Adobe, chicken wire and mud.
Shock absorbing foundations to adsorb the tremors. Often sunk into bedrock, avoiding clay.
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Cross-bracing is usually in an X shape. One brace will be under tension, while the other is compressed.
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