Natural Hazards

• Natural Hazards: naturally occurring events that occur, causing damage to property and affect human lives.
• Tectonic hazards: happen at plate boundaries/ margins due to movement
• Continental drift: movement of continents on the crust due to the movement of tectonic plates

  cause: (theory)

  • the outer core heats up particles in the mantle causing them to gain energy and rise
  • risen air cools down and sinks
  • cold air sinks and heated up and rise again
  • cycle of convention currents continues causing the movement of continents on the crust
• Types of tectonic plate

  • Oceanic plate: plates with ocean on it —> more denser
  • Continental plate: plates with land on it —> less dense
• Constructive/divergent play boundary

  • to continental plates move apart
  • magma rise on to surface, it cools and new crust is formed
  • low pressure and friction
  • gentle volcanic eruptions and earthquakes
• Destructive/ divergent plate boundary

  • oceanic plate and continental plate move together (converge)
  • the denser oceanic plate sinks under the continental plate into the subduction zone creating high pressure and friction.
  • results in violent volcanic eruptions and extreme earthquakes.
• Conservative plate boundary

  • two continental plate rubbing(grinding, moving) past each other
  • same direction, opposite direction, different speeds
  • no volcanic eruptions as no opening to mantle created
  • high friction causing earthquakes
• Colliding margin

  • two continental plates bumping into each other
  • earthquakes
  • fold mountains
• Case study: Nepal earthquake (LIC):

  7.8 magnitude, 8km deep focus, 60km from capital.

  Primary Effects

  • 9,000 people died(S)
  • 19,000 injured (S)
  • UNESCO sites destroyed(Ec)
  • 1000s of houses destroyed (S)
• Case study: Nepal earthquake (LIC):

  Secondary Effects:

  • Avalanche on Mount Everest killed 20 people(S)
  • Langtang Valley’s avalanche killed 250 people(S)
  • 1.7mil children displaced (S)
  • Harvest lost —> GDP lost (35% approx.) —> income lost (Ec n S)
  • Tourism affected as UNESCO sites destroyed—> income and jobs lost (Ec n S)
• Case study: Nepal earthquake (LIC):

  Immediate response:

  • $1bill given as aid by China and India
  • 100 search and aid responders, medical experts and 3 helicopters sent for gov’s use
  • red cross provided
  • temporary house/ tents provided
• Case study: Nepal earthquake (LIC):

  Long term response:

  • people educated by doing evacuation drills
  • UK donated £73mill and 81 tones of equipment provide
• Case study: New Zealand earthquake (HIC):

  6.3 magnitude, 5km deep focus

  Primary effects:

  • 181 dead, 2000 injured (S)
  • 100s of km of water pipes and sewage pipes destroyed (Ec)
  • 50% of building severely damaged (central city)(S)
  • Liquefaction damaged roads(Ec)
  • 80% of city was without electricity (S)
  • Country‘s largest glacier broke off into a glacier(En)
• Case study: New Zealand earthquake (HIC):

  Secondary Effects:

  • Businesses lost income from being out of action (S n EC)
  • schools had to share buildings due to damage (S n Ec)
  • liquefaction damage made it difficult for emergency services to move (S)
  • people affected mentally needed support (S)
• Case study: New Zealand earthquake (HIC):

  Immediate Responses:

  • $6-7mil provide as aid + aid workers
  • 30,000 chemical toilets provided for residents (reduced spread of disease )
  • most vulnerable moved away from dangerous buildings
• Case study: New Zealand earthquake (HIC):

  Long term:

  • $849mil paid in building claims
  • Temp housing provided and all damaged buildings kept more air tight
  • Sewage restored
  • roads and houses cleared of slit from liquefaction
  • 68% of roads and 50% of footpaths repaired
• Tropical storms:

  • Indian and south pacific ocean Cyclone
  • west of north Pacific Ocean typhoon
  • Atlantic and eastern Pacific Ocean hurricane
• Tropical storms: Conditions

  • hotter than 25 degrees Celsius water
  • large bodies if water
  • 50m deep
  • Around equator and Tropic of Cancer and Capricorn
  • most formed at Caribbean and south east Asia
  • Late summer/ early autum
• Tropical Storms: Formation

  • warm are from thunderstorms, warm (27 degrees +), deep (50m+) oceans mix together crating are of low pressure
  • Trade winds travel to equator which cause air mass to spin (also from Coriolis force)
  • hot air rise and cool trade winds are drawn in
  • Warm air condenses into cumulonimbus clouds
  • Warm air evaporates and rises and draws in more warm air from sea surface while pushing cool condense air back down (convection currents continue)
  • Colder drier air sinks in the centre creating calm conditions (in the eye)
• Tropical storm: Death

  • As they lose energy they slow down, lose power and die out
  • Landfall- reaches land and loses supply of warm moist air so convection currents stop
  • friction slows it down
• Track: path If the storm

  • usually tracks east to west due to the earth’s rotation

  Coriolis force: winds curve right in the northern hemisphere and winds curve left in the southern hemisphere

  Eye of the storm: centre with calm conditions

  Eye wall: strongest wind speeds

  • tropical storms wha e a spiral / vortex shape
• Saffir-Sampson hurricane scale: determines the wind power of the oncoming storm and therefore its damage of infrastructure. There are 5 categories. 1 is the weakest and 5 is the most catastrophic
• Case study: Philippines Typhoon Haiyan

  • south east asia
  • 8000 islands out of 11 are believed to be habited
  • ring of fire

  Primary effects:

  • 6,300 dead or missing
  • 90% of Tacoloban destroyed
  • 30,000 fishing boats destroyed
  • 40,000 homes destroyed
  • loss of electricity and infrastructure - 400mm rain and 5m high storm surge
• Case study: Philippines Typhoon Haiyan

  Secondary effects:

  • 14mil affected without food and water
  • mass burial (bereavement )
  • Flights and ferries that were supposed to provide aid disrupted
  • 6mil jobs lost and income lost
  • hospitals, schools, shops destroyed
  • violence and looting
  • disease outbreak
• Case study: Philippines Typhoon Haiyan

  Immediate responses:

  • red cross proved 1.1mil people with clean water
  • food and medical supplies distributed
  • US and Canada sent a helicopter for gov’s use
  • 1200 evacuation centre created (from school building and churches)
  • Tents and shelter provided
  • Cash for work program: locals were paid to clean up debris and medical waste
• Case study: Philippines Typhoon Haiyan

  Long term response:

  • Vaccinations to prevent spread of disease in future typhoon
  • 205,000 houses rebuilt with stronger infrastructure
  • Rice farming encouraged —> development agriculture sector
  • Mangrove forests grown reduce impact of storm surges and helps environment.