Natural and Tectonic Hazards

• Natural Hazard

  Extreme natural events that has potential to cause loss of life , extreme damage to property and disrupt human activities .
• Types of Natural Hazards

  Tectonic Hazards (examples: volcano eruptions , earthquakes )

  Climatic Hazards (examples: flooding , tropical storms )
• Factors affecting Hazard Risk

  Can have economic , social and environmental consequences . For each hazard event the risks of a particular consequence happening can vary greatly
• Plate Tectonics Theory

  Slab pull occurs where denser tectonic plates sink into the mantle at subduction zones . As these sections of plates sink , newer and less dense sections of plate are pulled along behind . Sinking in one place leads to plates moving apart in other places .
• Conservative Plate Boundary

  Plates move next to each other ( at different speeds ) or different directions

  ---> As they move next to each other friction builds plates then become stuck . Pressure builds up because the plates are still trying to move . When the pressure is released, it sends out huge amounts of energy , causing an earthquake
• Constructive Plate Boundary

  Two plates move away from each other due to convection currents

  --> movement creates friction of rock over the mantle = earthquake

  As a gap is created in-between the plates , magma from the mantle rises up to make a shield volcano
• Destructive Plate Boundary

  Plates move towards each other due to convection currents . Oceanic plate is more dense and sinks below continental in subduction - convection currents pull plates down through slab pull

  ---> If two continental plates collide it creates a collision margin due to a build up of friction pressure . Earthquakes occur

  Oceanic plate melts as it sinks into the mantle , forming magma . It escapes through weaknesses in the rock and rises through volcano causing an eruption
• Destructive Plate Boundary

  
• Constructive Plate Boundary

  
• Conservative Plate Boundary

  
• Haiti Earthquake ( 12th Jan 2010 )- LIC


  PRIMARY IMPACTS

  Over 220000 deaths

  30000 offices destroyed

  300000 people injured

  SECONDARY IMPACTS

  1.3mil made homeless

  Increase of cholera , 9000 died

  1 in 5 jobs lost
• Haiti Earthquake Responses

  SHORT TERM RESPONSES

  Dominican Republic donated water and medical supplies

  Red cross set up temporary field hospitals

  UN troops and police were sent to help distribute aid

  LONG TERM RESPONSES

  EU gave $330mil , International aid $3.5bil to rebuild

  Senegal offered education - 163 went

  Red cross received $500mil - promised 700 homes yet only built 6
• Tohoku Earthquake ( March 11 2011 ) -HIC


  PRIMARY IMPACTS

  332000 buildings destroyed

  11 hospitals destroyed - 300+ damaged

  800 after shocks of 4.5 magnitude

  SECONDARY IMPACTS

  $235bil cost of damage

  Tourism fell 62%

  300000 people displaced
• Tohoku Earthquake Responses

  SHORT-TERM RESPONSES

  100000 Japan Self defense were sent to help in search & rescue

  140000 residents evacuated near Fukushima

  Pacific Tsunami warning center able to detect seismic waves and immediately sent warning to Japan

  LONG-TERM RESPONSES

  Japan's red cross $16bil in donations

  GAP donated $1.1mil winter clothes

  $70mil spent on lasers to monitor the slightest movement
• Why people live in areas at risk from a tectonic hazard?

  Fertile soil - jobs w growing crops

  Cheaper housing and resources

  Friends and family live there
• Monitoring Risks of a Tectonic Hazard

  Earthquakes - seismometers and lasers monitor each movement

  Volcanoes - their shape , escaping gas , tiny earthquakes
• Predicting the Risks of Tectonic Hazards

  Volcanoes - if scientists monitor volcanoes closely

  Earthquakes - unreliable but possible if monitored ( tectonic plates )
• Protection from the Risks of Tectonic Hazards

  Volcanoes - buildings are strengthened and barriers to divert lava away

  Earthquakes - buildings strengthened and shut off switches for gas so no fire
• Planning for the Risk of Tectonic Hazards

  Emergency supplies

  Government planning evacuation routes

  Emergency services can prepare