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Natural Hazards

Natural Hazards. Natural Hazards?. A natural disaster (physical event) volcanic eruption Earthquake Landslide Human activity Ex: coastal settlement of populations. Basically…. A natural hazard is a naturally occurring event/phenomenon that has the ability to have an effect on

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Natural Hazards

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  1. Natural Hazards

  2. Natural Hazards? • A naturaldisaster (physical event) • volcanic eruption • Earthquake • Landslide • Human activity • Ex: coastal settlement of populations

  3. Basically….. A natural hazard is a naturally occurring event/phenomenon that has the ability to have an effect on people

  4. 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)

  5. 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

  6. So what is a natural disaster? a naturally occurring event/phenomenon that has had an effect on people Can you think of any?

  7. Can natural disasters have positive effects?

  8. 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

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

  10. 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

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

  12. 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

  13. Atmospheric Hazards Cyclonic Storms (hurricane, typhoon, cyclone) Tornado (twisters, dust devils) Severe Storm (White Juan, Nor’easter) Flooding (heavy rains) Drought (lack of rain, prolonged high pressure) Wildfire (wind, lightning) Severe Weather (hot/cold) ex: ice storm

  14. Biological Hazards Infectious Disease • HIV, H1N1, Bubonic Plague Parasitic Disease • ringworm Insect Infestation • malaria, West Nile virus

  15. Geological Hazards Slide (mud, land, rock) Volcanic Activity Earthquake Avalanche Tsunami (tidal wave)

  16. 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

  17. 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?

  18. 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

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