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  • Restless Earth
    • Earth's Layers
      • Core- Consists of a liquid outer core and a solid inner core.
      • Mantle- divided into solid upper part and semi liquid lower part, which can flow.
        • Convection Currents
          • 1) The core heats the molten rock in the mantle to create a convection current.
          • 2) Heated rock from the mantle rises to the Earth's surface.
          • 3) At the surface the convection currents move the tectonic plates in the crust.
          • 4) Molten rock cools and flows back to the core to be reheated.
      • Crust- made from thin layers of tectonic plates.
    • Types of Plate Boundaries
      • Destructive:
        • Example: Nazca Plate and South American Plate
        • Two plates collide, one plate flows beneath another (subduction)
        • Many earthquakes and volcanoes
      • Collision:
        • Example: Indo-Australian and Eurasian plates
        • Two continental plates collide and the two plates buckle
        • Many Earthquakes
      • Constructive:
        • Example: Eurasian and North American plates
        • Rising convection currents pull crust apart forming volcanic ridge.
      • Conservative:
        • Example: San Andreas Fault, California
        • Earthquakes
        • Two plates slide past each other
    • Type of volcano
      • Composite
        • found on destructive plate boundaries.Are formed by eruptions of viscous, sticky lava and ash that don't flow far.
      • Shield
        • found on constructive plate boundaries. Are formed by eruptions of thin, runny lava which flows a long way before it solidifies.
    • Managing earthquakes and volcanic hazards
      • Difficulties: Hard to predict. Exactly where it will happen. How big it will be. How many people live there.
      • Observations: Animales and birds moving away from the area. An increase in gas emissions. An increase in soil temperature. The volcano is  swelling. Water in ponds get warmer.
      • Buildings: Digging deeper foundations. Reinforce gas and water pipes so they don't break. Installing a ring beam at roof level to stop walls falling outwards.
      • Case Study:
        • Haiti Earthquake: 316,000 people died. Over 250,000 homes and 30,000 offices and factories destroyed or so badly damaged they had to be demolished. Roads blocked by rubble.
          • Primary Impacts
            • Injured and dead trapped under rubble.
            • People sleeping in the streets for fear of more earthquakes
            • Phone and power lines down
            • Streets blocked by huge piles of rubble from collapsed buildings.


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