Natural Hazards, Classification and Analysis


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An introduction to the concept of natural hazards,, a look at some of the ways they are classified and information about criteria used to analyze and compare natural hazards for Global Geography 12 at Charles P. Allen High School.

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Natural Hazards, Classification and Analysis

  1. 2. Natural Hazards? <ul><li>A natural disaster (physical event) </li></ul><ul><ul><ul><li>volcanic eruption </li></ul></ul></ul><ul><ul><ul><li>Earthquake </li></ul></ul></ul><ul><ul><ul><li>Landslide </li></ul></ul></ul><ul><li>Human activity </li></ul><ul><ul><ul><li>Ex: coastal settlement of populations </li></ul></ul></ul>
  2. 3. Basically….. <ul><li>A natural hazard is </li></ul><ul><li>a naturally occurring </li></ul><ul><li>event/phenomenon </li></ul><ul><li>that has an effect on </li></ul><ul><li>people </li></ul>
  3. 4. Vulnerability <ul><li>Vulnerability = susceptibility to injury or attack </li></ul><ul><li>Human vulnerability leads to financial, structural, and human losses. </li></ul><ul><li>Natural hazards only occur in inhabited areas </li></ul><ul><ul><li>A natural disaster in an uninhabited area has little tangible impact on people </li></ul></ul><ul><li>Natural hazards are increasing because of… </li></ul><ul><ul><li>Population growth (more people) </li></ul></ul><ul><ul><li>Urbanization (lots of people in small spaces) </li></ul></ul><ul><ul><li>alteration of the natural environment (manmade islands) </li></ul></ul>
  4. 5. Hazards’ Human Costs <ul><li>Every year natural disasters leave… </li></ul><ul><ul><li>4,000,000 homeless </li></ul></ul><ul><ul><li>46,000 injured </li></ul></ul><ul><ul><li>5520 dead </li></ul></ul><ul><li>These figures do not include the recent tsunami in Asia (273,000) and Hurricane Katrina (1000) </li></ul><ul><li>Source: The International Red Cross </li></ul>
  5. 6. Positive Effects <ul><li>natural disasters have beneficial ecological consequences. </li></ul><ul><ul><li>rejuvenation of a coniferous forest months and/or years after fires </li></ul></ul><ul><ul><li>recharging of groundwater stocks after a flood). </li></ul></ul><ul><ul><li>benefits tend to become apparent months or years after an extreme event </li></ul></ul>
  6. 7. Methods of Classification <ul><li>Calculating human costs </li></ul><ul><li>Impact measured by: </li></ul><ul><ul><li>loss of life (total deaths) </li></ul></ul><ul><ul><li>number of injuries </li></ul></ul><ul><ul><li>damage to property (replacement costs) </li></ul></ul>
  7. 8. Methods of Classification <ul><li>Strength/size/intensity of event </li></ul><ul><ul><li>Hurricane system </li></ul></ul><ul><ul><ul><li>Tropical depression, tropical storm, category 1-5 </li></ul></ul></ul><ul><ul><li>Tornado scale </li></ul></ul><ul><ul><ul><li>Force 1-5 </li></ul></ul></ul><ul><ul><li>Richter scale (seismic events) </li></ul></ul><ul><ul><ul><li>Scale of 1-9, with 9 being cataclysmic, worldwide event </li></ul></ul></ul><ul><ul><li>Epidemic, pandemic </li></ul></ul>
  8. 9. Methods of Classification <ul><li>Regional occurrence </li></ul><ul><ul><li>Hurricane (Atlantic) </li></ul></ul><ul><ul><li>Typhoon (Pacific rim) </li></ul></ul><ul><ul><li>Monsoon (Asia, Africa) </li></ul></ul><ul><li>Frequency of occurrence </li></ul><ul><ul><li>Annually? </li></ul></ul><ul><ul><li>Centenially? </li></ul></ul>
  9. 10. Disaster Categories <ul><li>We classify natural disasters by the chief process or sphere in which it operates </li></ul><ul><ul><li>Ex: Atmosphere, biosphere, lithosphere </li></ul></ul><ul><li>This system has three categories </li></ul>
  10. 11. Atmospheric Hazards <ul><li>Cyclonic Storms (hurricane, typhoon, cyclone) </li></ul><ul><li>Tornado (twisters, dust devils) </li></ul><ul><li>Severe Storm (White Juan, Nor’easter) </li></ul><ul><li>Flooding (heavy rains) </li></ul><ul><li>Drought (lack of rain, prolonged high pressure) </li></ul><ul><li>Wildfire (wind, lightning) </li></ul><ul><li>Severe Weather (hot/cold) ex: ice storm </li></ul>
  11. 12. Biological Hazards <ul><li>Infectious Disease </li></ul><ul><ul><li>HIV, H1N1, Bubonic Plague) </li></ul></ul><ul><li>Parasitic Disease </li></ul><ul><ul><li>ringworm </li></ul></ul><ul><li>Insect Infestation </li></ul><ul><ul><li>malaria, West Nile virus </li></ul></ul><ul><li>Plant Disease </li></ul><ul><ul><li>Dutch Elm disease, blight </li></ul></ul>
  12. 13. Geological Hazards <ul><li>Slide (mud, land, rock) </li></ul><ul><li>Volcanic Activity </li></ul><ul><li>Earthquake </li></ul><ul><li>Avalanche </li></ul><ul><li>Tsunami (tidal wave) </li></ul>
  13. 14. Comparison and Analysis <ul><li>Any one disaster can be described by analyzing various factors that determine how great an impact it will have on people </li></ul><ul><li>This system recognizes six main factors </li></ul>
  14. 15. Comparison and Analysis <ul><li>Frequency </li></ul><ul><ul><li>how often is the event likely to happen </li></ul></ul><ul><li>Duration </li></ul><ul><ul><li>the length of time the event lasts </li></ul></ul><ul><li>Extent </li></ul><ul><ul><li>Size of area or region affected </li></ul></ul><ul><ul><ul><li>Town? Continent? Region? </li></ul></ul></ul>
  15. 16. Comparison and Analysis <ul><li>Speed of onset </li></ul><ul><ul><li>sudden, without warning, over quickly? </li></ul></ul><ul><ul><li>build slowly before a peak period </li></ul></ul><ul><li>Spatial dispersion </li></ul><ul><ul><li>area likely to be affected by a particular event </li></ul></ul><ul><li>Temporal spacing </li></ul><ul><ul><li>how hazards and disasters occur in time; are they random or do they occur within a cycle </li></ul></ul>