Exposure and Vulnerability to Hazards

• The exposure of people to risks and their ability to cope with tectonic hazards changes overtime.

  Geophysical events like volcanic eruptions and earthquakes become hazards when they start to pose a threat to people.

   

  The disaster risk equation can be used to give an indication of the hazard vulnerability for a location:

   

  Risk = Hazard X Vulnerability/Capacity to Cope
• What factors affect the physical exposure to earthquakes/volcanoes?

  ·         Frequency of the event.

  ·         Magnitude of the event.

  ·         Types of hazards generated in a given location.

  ·         Number of people living in a disaster prone area.

   

  Generally, the greater the magnitude of an event, the less frequently an event occurs.

  High magnitude events usually have a longer recurrence interval (time between events).

   

  Resilience is about how well an individual or society is able to function at an acceptable level when a destabilising force has affected them.
• ·         When a tectonic disaster strikes, there is often a pattern of impacts. This can be shown on Parks model.

  ·         All disasters have a slightly different curve depending on numerous factors including:

  o   Type of hazard (earthquake/volcanic eruption).

  o   Number of people affected.

  o   Wealth/level of development.

  o   How vulnerable/resilient they are.

   
• Mitigation:

   

  Mitigation is the action of reducing the severity, seriousness or painfulness of something.

   

  Modifying the event:

  ·         Not possible for the vast majority of volcanic eruptions.

  ·         However, the following have been tried with some success:

  o   Lava-diversion channels.

  o   Spraying lave to cool it, so it solidifies.

  o   Slowing lava flows by dropping concrete blocks.

  ·         Nothing can be done to modify the event in the case of earthquakes.
• Modifying the vulnerability


  1. Education

  2. Community preparedness

  3. Prediction and warning

  4. Hazard-resistant building design

  5. Hazard mapping

  6. Land use zoning
• Education


  • Ensuring people can recognise the signs of a possible eruption
  • Making sure they know what to do should one erupt, or an earthquake hit
• Community preparedness


  • Building of tsunami shelters and walls
  • Strengthening public buildings
• Prediction and warning


  • Increasing the use of technology to monitor tectonically active locations
• Hazard-resistant building design


  • Cross bracing of buildings to support them during an earthquake
  • Steep sloping roofs to prevent ash building up
• Hazard mapping


  • Predicting lahar routes
  • Predicting ground that's likely to liquify during an earthquake
• Land use zoning


  • Avoiding building in locations identified through hazard mapping
• Modifying loss:

  ·         Emergency aid.

  ·         Disaster response teams and equipment.

  ·         Search and rescue strategies.

  ·         Insurance for buildings and businesses.

  ·         Resources for rebuilding public services.