Natural hazards

• A Natural Hazard is a Threat to People or Property
• Natural hazard


  • A natural process which could cause death, injury or disruption to humans, or destroy property and possessions
• Natural disaster


  A natural hazard that has actually happened
• Extreme events which do not pose any threat to human activity are not counted as hazards (eg, a drought in an uninhabited desert or an avalanche in Antarctica)
• Two Main Types of Natural Hazard

  • Geological Hazards
  • Meteorological Hazards
• Geological Hazards


  • Caused by land and tectonic processes, including volcanoes, earthquakes, landslides and avalanches
• Meteorological Hazards

  • Caused by weather and climate, including tropical storms and other extreme weather like heatwaves and cold pulses
• Hazard risk

  The probability of people being affected by a hazard in a particular area
• Factors affecting hazard risk

  • Vulnerability (more people exposed, higher probability of being affected)
  • Capacity to cope (higher income countries better able to cope)
• Factors affecting hazard risk

  • Type (some hazards have greater risk than others, e.g. sudden vs predictable)
  • Frequency (hazards that occur more often may carry higher risk)
  • Magnitude (more severe hazards tend to have greatest effects)
• A magnitude 9.0 earthquake that struck Japan in 2011 killed over 15,000 people, whereas a 6.3 magnitude earthquake in L'Aquila, Italy, in 2009 killed around 300 people
• Primary effects of natural disasters

  • Immediate impacts like buildings/roads destroyed, people injured/killed, crops/water supplies damaged, infrastructure disrupted
• Secondary effects of natural disasters

  • Hazards triggering other hazards, blocked access hampering emergency response, disease spread, food shortages, economic damage
• Immediate Responses to natural disasters

  • Evacuate people
  • Treat injured, rescue trapped
  • Recover dead bodies
  • Provide temporary utilities
  • Provide food, drink, shelter
  • Foreign aid
• Long-Term Responses to natural disasters

  • Repair/rebuild homes, buildings, infrastructure
  • Reconnect utilities
  • Improve forecasting, monitoring, evacuation plans
  • Improve building regulations
  • Boost economic recovery