hazards factors

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  • Factors affecting the scale of a natural disaster
    • Duration of Impact and warning time
      • Sudden impact hazards- hazards which occur fast and with little warning
      • Slow onset or creeping hazards- take longer to occur
    • Population density
      • the more people that live in an area, the higher the risk of disaster
      • an earthquake in Alaska will have less impact than one which hits a more densely populated area such as San Francisco
        • The Pacific Ring of fire covers a 40,000km horseshoe shape and has around 90% of the world’s earthquakes and 452 volcanoes.
          • Hundreds of millions of people live in this zone, including over 20 million people close to Popocatépetl volcano in Mexico
        • 90% of hazard related deaths occur in LEDCs, whilst 75% of economic hazards occur in MEDCs.
    • Magnitude
      • the higher the magnitude of the disaster, the worse the effects
      • every step up the Earthquake Richter scale represents a 10 fold increase in damage and a 30 fold increase in energy released.
    • Frequency
      • The more often a hazard occurs generally the more prepared people are, and the more used to coping they are
      • Large earthquakes and volcanic eruptions are generally very rare
      • frequent events allow people to adjust their buildings and lives to cope with the risk associated.
      • the more often an event occurs, the higher the perception of risk and therefore better preparation
    • Time
      • the more time people know about the hazard, the better prepared they can be
      • the time of day the event occurs impacts on the effects.
        • At night, the effects will be worse as people will be asleep
      • media and communications resulted in events being reported quicker
    • Preparation
      • a place which is well prepared can limit the impacts of the hazard
      • this is when strategies are put in place to limit damage
        • educating  local people; can reduce impacts by making them more prepared
    • Development
      • High Income Countries (HIC) are much better at preparing and responding to natural hazards
        • better access to technology
          • can predict events
        • less resourced to cope with hazard
      • agencies and governments
        • quick response
    • Natural Factors
      • height of land
        • land above sea level will be less likely to flood
      • shape of coastline
        • gently sloping coastline will suffer more damage than steep coastline
        • tsunami
      • geology
        • softer sediments more likely to liquefy
          • can result in building collapse
        • earthquake shaking in soft sediments usually larger and longer

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