Natural Hazards

• Factors affecting hazard risk

  • Development (LICs more at risk due to lack of safe housing or defences)
  • Climate change (increased risk of more intense and frequent hazards in more areas)
  • Urbanisation (more people living in urban areas means more damage when buildings collapse)
  • Land use (densely populated areas more at risk than sparsely populated areas)
• The San Andreas fault in California is an example of a conservative plate boundary
• Japan is an example of a destructive plate boundary
• Constructive Boundaries

  • Magma rises in the gap left by the two plates pulling apart
  • Forms shield volcanoes
  • Earthquakes occur as plates shake and vibrate as they move apart
• Destructive Boundaries


  • Oceanic crust is subducted below the less dense continental crust
  • Creates an ocean trench
  • Friction causes strong earthquakes
  • Oceanic crust is melted, creating magma
  • Pressure builds up and pushes through crust, forming explosive volcanoes
• Collision Boundaries 


  • plates push together
  • neither can be subducted so crumple upwards
  • this creates fold mountains
• Conservative Boundaries


  • parallel plates moving in different directions or at different speeds
  • can get stuck, friction builds
  • plates eventually releasing sends a sudden jolt as an earthquake
  • on oceanic crusts this can cause tsunamis