Natural Hazards

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Natural Hazards
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Natural Hazards?

• A natural disaster (physical event)
• volcanic eruption
• Earthquake
• Landslide
• Human activity
• Ex coastal settlement of populations

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Basically..

• A natural hazard is
• a naturally occurring
• event/phenomenon
• that has an effect on
• people

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Vulnerability

• Vulnerability susceptibility to injury or
  attack
• Human vulnerability leads to financial,
  structural, and human losses.
• Natural hazards only occur in inhabited areas
• A natural disaster in an uninhabited area has
  little tangible impact on people
• Natural hazards are increasing because of
• Population growth (more people)
• Urbanization (lots of people in small spaces)
• alteration of the natural environment (manmade
  islands)

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Hazards Human Costs

• Every year natural disasters leave
• 4,000,000 homeless
• 46,000 injured
• 5520 dead
• These figures do not include the recent tsunami
  in Asia (273,000) and Hurricane Katrina (1000)
• Source The International Red Cross

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Positive Effects

• natural disasters have beneficial ecological
  consequences.
• rejuvenation of a coniferous forest months and/or
  years after fires
• recharging of groundwater stocks after a flood).
• benefits tend to become apparent months or years
  after an extreme event

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Methods of Classification

• Calculating human costs
• Impact measured by
• loss of life (total deaths)
• number of injuries
• damage to property (replacement costs)

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Methods of Classification

• Strength/size/intensity of event
• Hurricane system
• Tropical depression, tropical storm, category 1-5
• Tornado scale
• Force 1-5
• Richter scale (seismic events)
• Scale of 1-9, with 9 being cataclysmic, worldwide
  event
• Epidemic, pandemic

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Methods of Classification

• Regional occurrence
• Hurricane (Atlantic)
• Typhoon (Pacific rim)
• Monsoon (Asia, Africa)
• Frequency of occurrence
• Annually?
• Centenially?

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Disaster Categories

• We classify natural disasters by the chief
  process or sphere in which it operates
• Ex Atmosphere, biosphere, lithosphere
• This system has three categories

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Atmospheric Hazards

• Cyclonic Storms (hurricane, typhoon, cyclone)
• Tornado (twisters, dust devils)
• Severe Storm (White Juan, Noreaster)
• Flooding (heavy rains)
• Drought (lack of rain, prolonged high pressure)
• Wildfire (wind, lightning)
• Severe Weather (hot/cold) ex ice storm

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Biological Hazards

• Infectious Disease
• HIV, H1N1, Bubonic Plague)
• Parasitic Disease
• ringworm
• Insect Infestation
• malaria, West Nile virus
• Plant Disease
• Dutch Elm disease, blight

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Geological Hazards

• Slide (mud, land, rock)
• Volcanic Activity
• Earthquake
• Avalanche
• Tsunami (tidal wave)

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Comparison and Analysis

• Any one disaster can be described by analyzing
  various factors that determine how great an
  impact it will have on people
• This system recognizes six main factors

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Comparison and Analysis

• Frequency
• how often is the event likely to happen
• Duration
• the length of time the event lasts
• Extent
• Size of area or region affected
• Town? Continent? Region?

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Comparison and Analysis

• Speed of onset
• sudden, without warning, over quickly?
• build slowly before a peak period
• Spatial dispersion
• area likely to be affected by a particular event
• Temporal spacing
• how hazards and disasters occur in time are they
  random or do they occur within a cycle