tectonic hazards

• a natural hazard is a sudden event that makes the natural environmnet difficult to manage
• factors that affect hazard risk

  1. farming - nutrients rich lands of floodplains
  2. urbanisation - higher population in flooding area
  3. poverty - people build on poor land or have poor houses
  4. climate - rising sea levels
• an eathquake is a sudden violent shaing
• earthquakes mainly occur at plate boundaries
• an oceanic crust is more dense, thin and can be destroyed
• a continental crust is less dense, thick and cannot be destroyed
• plates move driven by a convection current in deep mantle
• volcanoes are large cone shaped landforms
• volcanoes are fed by magma deep underground and they mostly occur in belts across plate margins
• some volcanoes can occur in hots pots where there is a thin crust and magma can rise to the surface
• a constructive plate margin is where the plates move away from each other and magma forces its way through the surface
• a conservative plate margin is when the plates move alongside each other
• a destructive plate margin is when the plates move towards each other
• in a destructive plate margin the oceanic crust is subducted beneath the less dense continental crust this causes friction which can lead to earthquakes . the sinking oceanic crust also causes sticky, gas-filled magma to rise which can flow a long way without cooling which forms volcanoes that violently erupt
• at constructive plate margins as the plates move away from each other magma forces itself up through the surface, the magma is very hot allowing it to flow a long way without cooling so broad fat shield volcanoes formed eg mid Atlantic ridge. as the magma breaks the surface this can cause mild earthquakes
• if 2 continental crusts meet there is no subduction zone meaning no magma causing the crust to crumple which lifts to form fold mountains e.g. Himalayas
• at conservative plate margin as 2 plates move alongside each other it creates friction which builds stress and earthquakes occur when they slip
• no volcanoes occur at conservative plate margins
• the earths core is hot which makes the mantle hot o magma rises as it becomes less dense it then cools and condenses and becomes more dense so sinks
• earths structure

  1. inner core - solid nickel and iron
  2. outer core - liquid nickel and iron
  3. mantle - molten rock
  4. crust - solid rock
• ridge push 


  at a constructive plate margin ocean ridges form high above ocean floor from solidified lava. magma rises between the plates and cool to form new plate materials. as it rises it becomes dense and slides down away from ridge
• slab pull


  at destructive plate margins the denser oceanic crust sinks back into the mantle from gravity, this pulls the plates along behind it
• why do people work near hazards

  the fat geezers
• volcanoes create ash clouds which can lead to air travel being disrupted, crops destroyed and houses collapsing
• earthquakes are shaking of ground which can lead to pipelines being destroyed which can lead to fires and floods
• people are attracted to areas of tectonic hazards because...

  1. tourist attractions
  2. farming
  3. geothermal energy
• mount Fuji has major tourist industry
• mount agung has very fertile land and wet for growing crops like rice
• in iceland 20% of energy is from geothermal energy
• geothermal energy is where magma is located near surface which heats water and turns it into steam which is an renewable energy source
• reducing tectonic hazards

  my pretty pink pony
• reducing tectonic hazards

  1. monitoring
  2. predicting
  3. planning
  4. protecting
• monitoring for volcanoes

  1. ground deformation
  2. escaping gases
  3. seismic activity
• predict volcanoes because they are closely monitored so an evacuate
• its virtually impossible to protect against volcanoes can try to divert lava
• earthquakes can be monitored by watching ground deformation, water pressure and animals fleeing
• earthquakes cannot be predicted
• can prevent against earthquakes with...

  1. reinforced concrete which absorbs energy from earthquakes to stop buildings collapsing
  2. automatic shutter windows to prevent glass shattering
  3. steel frames gives strength to stop building collapsing
• planning for earthquakes and volcanoes

  1. train emergency services
  2. evacuation routes
• latitude is the distance from the equator