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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 an effect on people. Terms to Know.

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Natural Hazards

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  1. Natural Hazards

  2. Natural Hazards? • A natural disaster (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 an effect on people

  4. Terms to Know Hazard - a threat (natural or human) that has the potential to cause loss of life, injury, socio-economic disruption or environmental degradation.

  5. Terms to Know Disaster - a major hazard that causes widespread disruption with significant demographic, economic and environmental loss. The affected community needs outside help.

  6. 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)

  7. Terms to Know Risk - the probability of a hazard event causing harmful consequences. Expected losses, death injury etc.

  8. 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

  9. Natural Disaster Quotes • Mr. Speaker, from hurricanes and floods in Latin America to earthquakes in Asia, natural disasters are increasingly becoming a regular feature of life for large numbers of people around the globe. Earl Blumenauer

  10. Quote to Elaborate • a world full of competing emergencies and disasters, it really helps if there is an international locomotive that can help us bring attention - help us bring resources. Jan Egeland • Did you know that the word "tsunami," which is now being used worldwide, is a Japanese word? This is indicative of the extent to which Japan has been subject to frequent tsunami disasters in the past. Junichiro Koizumi

  11. 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

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

  13. 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

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

  15. 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

  16. 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

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

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

  19. 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

  20. 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?

  21. 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

  22. Earthquakes Earthquakes occur along the boundaries of the tectonic plates of the earth’s crust. When these plates come in contact with each other, the pressure builds up and an earthquake occurs.

  23. Tectonic Plates

  24. Types of Earthquakes Convergent Boundaries - When two plates collide together. This created the Himalayan mountains. Subduction occurs when one oceanic plate goes under a land plate. Created the Andes Mountains.

  25. Types of Earthquakes Divergent - When two plates are moving apart.

  26. Types of Earthquakes Transform Boundaries - when two plates slide past each other. This is occurring along the San Andreas Fault in California.

  27. Earthquakes - Human Causes Nuclear testing Building large dams Drilling for oil and gas Coal mining

  28. Factors Affecting Earthquake Damage Strength and depth of earthquake, and number of aftershocks. Population density

  29. Factors Affecting Earthquake Damage Time of Day Types of rock and sediments that buildings are built on. Secondary hazards Economic development

  30. Factors Affecting Earthquake Damage - MEDCs vs. LEDCs Type of buildings - MEDCs countries tend to have better quality buildings and insurance than LEDCs. More prepared (ability to predict) More effective emergency services Funds to rebuild Relationships with other MEDCs

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