Tectonics

• Crust – most external layer, protective layer, very thin, coolest layer, it is a solid hard layer, it is made up of two types of crust, oceanic and continental, 900 degrees Celsius 
• Mantle – thickest layer, some parts are solid and some parts are in a liquid state (molton), protective layer for the inner and outer core, 1600-4000 degrees Celsius 
• Outer core – 4000 – 5000 degrees Celsius, liquid layer, acts as a protector to the inner core, has a high temperature as it is near the inner core 
• Inner core – most internal area, hottest layer, 5000 degrees Celsius, solid, made of two minerals, iron and nickel 
• Radioactive decay – involves the disintegration of natural radioactive elements inside earth – like uranium, for example. Uranium is a special kind of element because when it decays, heat is produced. 
• Residual heat – a lot of earth’s heat is leftover from when our planet formed four-and-a-half billion years ago. 
• Convection currents – circular current of heat in the mantle 
• Slab pull – older, colder plates sink at subduction zones, because as they cool they become denser than the underlying mantle. The cooler sinking plate, pulls the rest of the warmer plate behind it 
• Subduction - The process whereby a dense oceanic plate sinks back into the upper mantle 
• Fold Mountains - Chains of high mountains produced when tectonic plates collide and the continental crust crumbles and is forced upwards 
• Divergent plates – formed when two plates move apart 

  Convergent plates – formed when two plates collide 

  Conservative plates – formed when two plates slide past each other 
• Effects of the Sendal Earthquake: 

  1 dam collapsed - social 

  2 nuclear power plants damaged - social 

  Oil refinery set on fire - social 

  Motorway badly damaged - social 

  Airports closed – social  

  Rail link badly damaged – economic  

  $235 billion in damages – economic  

  16,000 died - social 

  2,600 missing - social 

  6,000+ injured - social 

  350,000 homeless - social 

  Most people were at school or work since it was 2:46pm - social 

  Business disrupted – social/economic 

  Schools disrupted – social 
• Haiti: 

  Magnitude 7 

  316k died 

  350k injured 

  1m people were homeless 

  Collapsed building/roads 

  Rubble and rail links destroyed 

  Water destroyed which lead to a cholera outbreak 

  Port was destroyed 

  Clothing factories destroyed 

  60% of people were jobless 

  4 years for most people to be housed again