Unit 1A-Tectonic Hazards

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  • Tectonic Hazards
    • Types of plate margin
      • Destructive
        • Two plates moving towards eachother
        • When there is an oceanic and continental plate, the denser oceanic plate is forced to subduct
          • Create volcanoes and ocean trenches
        • When two continental plates collide, the ground is folded and forced upwards
          • Create fold mountain ranges
      • Constructive
        • Two plates moving away from eachother, for example the Mid-Atlantic ridge
          • Causes magma to rise and fill the gap forming new crust when it cools
      • Conservative
        • Two plates moving sideways past eachother, or the same direction but at different speeds for example the West coast of the USA
          • No crust is created or destroyed
    • Tectonic plates
      • The crust is seperated into slabs called tectonic plates
      • Continental plates are thicker,30-50km thick and less dense
      • Oceanic plates are thinner,5-10km thick and more dense
      • They move due to convection currents
      • The place where they meet is called a plate margin
    • Volcanoes
      • At destructive plate boundaries, the oceanic plate that has been subducted and destroys forms a pool of lava which then rises through the vent of a volcano and erupts out.
      • At constructive plate boundaries, magma rises through the gap created by the plates moving apart
      • Some form over parts of the mantle "hotspots" such as Hawaii
      • Volcanoes emit lava, gases and ash which can lead to pyroclastic flows(super heated currents of gas, ash and rock)
      • Effects
        • Primary
          • Buildings and roads destroyed
          • People and animals killed or injured
          • Crops and water supplies damaged
          • People, animals and plants suffocated by volcanic gases
        • Secondary
          • Mudflows or lahars when water mixes with volcanic material
          • Flooding caused by melting snow and ice
          • Transport networks blocked or destroyed
          • People left homeless
          • Tourism disrupted
          • Ash makes fields more fertile when it breaks down
          • Recovery can be very expensive and time-consuming
      • Responses
        • Immediate
          • Evacuate people before the eruption
          • Provide food, drink and shelter
          • Treat people injured in the eruption
          • Rescue anybody cut off by damage to roads or bridges
          • Provide temporary electric, gas and communication supplies
          • Aid workers sent in to support areas
          • Tech companies set up disaster response tools
        • Long term
          • Repair and rebuild, or resettle affected people
          • Repair and reconnect infastructure
          • Improve and repair monitoring systems
          • Untitled
    • Earthquakes
      • Responses
        • Immediate
          • Rescue people trapped, and treat injured people
          • Recover dead bodies
          • Put out fires
          • Set up temporary shelter
          • Provide temporary supplies
          • Aid workers sent to the area
          • Tech companies set up disaster response tools
        • Long-term
          • Re-house people
          • Repair or replace damaged buildings
          • Reconnect broken electric, water and gas connections
          • Improve building regulations
          • Promote economic recovery
      • Effects
        • Primary
          • Buildings and bridges destroyed
          • People injured by collapsed buildings or debris
          • Transport links damaged
          • Electrics, gas and water supplies damaged
        • Secondary
          • Can trigger landslides and tsunamis
          • Leaking gas may set on fire
          • People left homeless, could die
          • Lack of clean water and sanitation
          • Difficult access
          • Businesses damaged
          • Weakened economy
    • Managing tectonic hazards
      • Monitoring
        • Networks of seismometers and lasers to monirot earth movements
        • Scientists can monitor the signs before a volcanic eruption
      • Prediction
        • Monitoring and forecasting
        • Keeping a close eye on active volcanoes
      • Protection
        • Buildings designed to withstand
        • Existing structures strengthened
        • Automatic shut off switches implemented
      • Planning
        • Future developments planned properly
        • Training for the emergency services
        • Education and evacuation routes implemented

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