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Natural Hazards

Natural Hazards. Ellen Metzger April 12, 2014. Outline. Why Natural Hazards? Application of NGSS science and engineering knowledge and practices to a complex, real-world problem Engaging example of the interactions among natural and human systems Overview of Natural Hazards

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Natural Hazards

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  1. Natural Hazards Ellen Metzger April 12, 2014

  2. Outline • Why Natural Hazards? • Application of NGSS science and engineering knowledge and practices to a complex, real-world problem • Engaging example of the interactions among natural and human systems • Overview of Natural Hazards • Bringing it home • What natural hazards affect the Bay Area/California? (online activity this afternoon)

  3. Sources • http://www2.fiu.edu/…/Natural%20Hazards.ppt • http://wwwrcf.usc.edu/~pochen/GeologicalHazards_Lessons/L1.pptx.pdf • Your Planet Earth:http://www.earth4567.com/talks/hazards.html

  4. Overview of Natural Hazards Natural hazards are inevitable but natural disasters are not. Why? American Geological Institute Big Ideas in Earth Science Big Idea 8: Natural Hazards Pose Risks to Humans http://www.youtube.com/watch?v=n73qtEojP_Y Sources http://www2.fiu.edu/…/Natural%20Hazards.ppt http://www-rcf.usc.edu/~pochen/GeologicalHazards_Lessons/L1.pptx.pdf Your Planet Earth:http://www.earth4567.com/talks/hazards.html

  5. Introduction to Natural Hazards • What is a “Geohazard”? • Earth processes (involving the lithosphere, hydrosphere & atmosphere) that, upon interaction with human activity, cause loss of life and property • It is important to understand the human element • without it, there would be no hazard • because of it, the science of natural hazards becomes more important every year Mitigation: reduction/prevention Hazardousconditionor result geo-process humanprocess

  6. Why is the human element so critical? Earth’s population is increasing • More people living in hazard-prone areas • Populations are becoming hyper-concentrated • Examples: • today there are 6 billion people on Earth ( ~ 50% live in cities) • by 2025, there will be ~8 billion people (~ 66% in cities) • of these cities, 40% are coastal • prone to severe storm and tsunami damage • and a large majority lie in areas subject to other geohazards (for example volcanoes and earthquakes) Next: Before and after photographs from Phuket, Thailand, of the 2004 Boxing Day (26th of December) tsunami.

  7. CANNOT stop the geologic processes • CANNOT stop the population growth/expansion • Therefore, we must try to reduce (mitigate) the hazards through: • Scientific study • Population education • Changes in engineering/building practices • Management plans and hazard response scenarios

  8. Hazards Fundamental Principles: • Natural hazards can arise from external or interior Earth processes • Risk Analysis is important for understanding impact • Hazards are linked, e.g., volcano, earthquake, tsunami, landslide, flooding, forest fire. • Human interference is magnifying damage • Consequences can be minimized

  9. Types of Natural Hazards • Volcanoes, floods, earthquakes, tornadoes, tsunamis, etc. • can act adversely on human processes • can occur: • without warning (e.g. earthquakes) • with warnings (precursors) (e.g. satellite monitoring of cyclone tracks, or the presence of ground deformation at a volcano before an eruption)

  10. Flooding along Colorado’s Front Range. Sept. 2013. USGS Damage from a magnitude 6.6 earthquake in Sichuan, China, on April 20, 2013. USGS  "Rim Fire“ near Yosemite National Park. August-November, 2013. Source NPR Oso, Washington, March 2014. Wikipedia.

  11. Animation: Oso Landslide http://www.youtube.com/watch?v=jZhuLThlCgQ

  12. Population increase, land-use change, and natural hazards Population increase and hazardous events • as population increases, need for planning to minimize losses from natural disasters also increases • a. more people at risk of an event • b. forces more people into hazardous areas Land-use change and hazardous events • past half-century has seen dramatic increase in great catastrophes • vast majority of natural disaster deaths between 1985-1995 were in developing world (equity/vulnerability/resiliance) • Hurricane Mitch: hillsides stripped because of heavy rains on cleared and burned land • Yangtze River: timber harvest and conversion to agriculture has increased flood hazard

  13. Disaster Prediction • Location: • e.g., Volcanoes and earthquakes along plate boundaries • Probability of occurrence • Hazards are cyclical, • With sufficient data probability of occurrence can be calculated • Precursor events • Volcanoes, earthquakes, landslide, flooding..often associated with precursor events • Forecasting • Is possible by monitoring hazards e.g., hurricanes, tsunamis, volcanic eruption etc • Warning • Should be issued even at the risk of the hazard not materializing

  14. Risk Assesment • Risk Determination • Risk= probability X damage • Acceptable Risk • Risk-tolerance level of the society • Can vary: High for automobiles but low for nuclear accident • Problem and opportunities • Lack of long term data– how do we calculate risk? • Information may be complex and difficult to analyze e.g., what is the effect of radiation leak from a nuclear reactor? • Better risk assessment will lead to better decisions

  15. Human Response to Natural Hazards Reactive – traditional response • Impact • Direct (People killed, property damaged – affects individuals or small groups) and • Indirect effects (mental trauma, tax, donations—affects population) • Stages: • Emergency: Search and Rescue, shelter, opening roads • Restoration: water and power, return to home, cleaning of rubble • Reconstruction I: Return to pre-disaster level • Reconstruction II: improvement • Rapid Restoration can be counter-productive

  16. Human Response to Natural Hazards • Anticipatory – a better way to reduce damage • Hazard perception by people and by government • Land-use planning: avoid hazardous locations • Insurance: often not extended to high risk areas • Evacuation • Disaster preparedness • Artificial control • Difficult, expensive and often cause more harm • Channelization of Mississippi River • Sea walls, dams…

  17. Future trends • Global Climate and hazard • Global warming is increasing weather-related disasters • Population and hazard • Greater population density leads to higher risk • Change in land-use pattern magnifies damages • Recent floods in Haiti related to deforestation

  18. Global climate and hazards Global and regional climate change may significantly affect incidence of storms, landslides, drought, fires Climate change may affect magnitude and frequency of natural events • sea level rise may increase coastal erosion • shift in food production areas • expansion of deserts and semi-deserts Warming of oceans will channel more energy from ocean water into atmosphere • Likely will increase hazardous weather-related processes

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