Natural Hazards

All infomation from CGP geography 9-1 revision guide

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  • Created by: L1ttle M
  • Created on: 19-03-18 19:52
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  • Natural Hazards
    • Earthquakes
      • can happen at all three types of plate margin
      • caused by tension building up at the plate margin
        • Conservative margins - tension builds up when plates that are grinding past each other get stuck
          • the plates eventually jerk past each other, which causes vibrations known as earthquakes
            • Constructive Margin - tension builds along cracks within the plates as they move away from each other
            • the shock waves spread out from the focus, the closer to the focus the stronger the waves and the more damage caused
              • focus - the point in the earth where the earthquake starts
        • Constructive Margin - tension builds along cracks within the plates as they move away from each other
        • Destructive Margins - tension builds up when one plate gets stuck as it's moving down mast the other into the mantle
          • the plates eventually jerk past each other, which causes vibrations known as earthquakes
            • the shock waves spread out from the focus, the closer to the focus the stronger the waves and the more damage caused
              • focus - the point in the earth where the earthquake starts
      • the epicentre - the point on the earth's surface directly above the focus.
      • measured using the moment magnitude scale
    • Volcanoes
      • destructive plate margins
        • the oceanic plate goes under the continental plate because it is denser
        • the oceanic plate moves down into the manltle where it is melted and destroyed
          • a pool of magma forms
            • the magma rises through cracks in the mantle called vents
              • the magma erupts onto the surface forming a volcano
      • constructive margins
        • magma rises up into the gap created by the plates moving apart forming a volcano
      • some volcanoes form over parts of mantle that are really hot (hot spots)
        • for example in Hawaii
      • when a volcano erupt it emits lava and ash
        • some volcanoes emit lots of ash
          • it can cover land
          • it can block out the sun
          • it can form pyroclastic flows

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