Our Hazardous Environment GEOG 1110 Dr. Thieme

1. Our Hazardous EnvironmentGEOG 1110Dr. Thieme Scientific Method, Forecasts, Prediction, and Risk Assessment

2. Scientific Method • make observations • formulate a hypothesis • test the hypothesis with new observations • draw conclusions (build a "theory")

4. Scientific Hypothesis • a tentative assumption that is made for the purpose of a study. • testable against data obtained by experiment or from field observation • disproving your hypothesis thereby confirms its opposite ornull hypothesis

5. Observation: A landslide occurred and destroyed three homes • Hypothesis:Water on the hillslope, seeping from a buried waterline, caused the landslide

6. Risk Assessment • using statistical methods to quantify the risks involved in a particular action • risks are compared and contrasted before deciding how to act • risks are evaluated in order to identify the causes of a medical condition or an environmental problem

7. Risk • probability calculated as a fraction: • 0 (certain not to occur) • 1 (certain to occur) • multiplied by the consequences • consequences can be harm or loss to: • people • property • economic activity • public service....

8. Risk Analysis • estimate the probability that an event will occur and the consequences resulting • Los Angeles has a 5 percent chance of a moderate earthquake (p = 0.05)

9. Risk Analysis • large events have lower probability than small ones • but consequences tend to be greater Acceptable Risk - the risk that society or individuals are willing to take • businesses calculate risk in economic terms • individuals also incur risk

10. Risk Analysis and Planning • delineate areas where hazards occur • identify the processes responsible • attempt to control nature ("flood control")? • provide maps and information to planners and decision maker in order to • avoid putting people and property in harm's way

11. Avoiding Disasters • Land Use Changes: Avoid building on • floodplains • areas where there are active landslides • places where coastal erosion will occur • Insurance (flood, earthquake, etc...) • Evacuation • Preparedness - Train individuals and institutions to handle large numbers of injured and limit mass hysteria

12. Flow Path for Predicting or Warning about a Natural Disaster

13. Prediction and Forecast • Prediction involves specifying date, time, and size of an event (flood resulting from tropical storm, etc...) • Forecast is a prediction with a range of certainty (and uncertainty!) • For some types of natural hazard, neither prediction nor forecast is really possible • Some assessment of risk is always possible

14. Precursor Events • linked with a hazardous event either causally or statistically • Foreshocks or unusual uplift of land may precede earthquakes • Volcanoes sometimes swell or bulge before they erupt • Sea may withdraw suddenly from a beach before a tsunami hits

15. Natural Hazard Impacts • Magnitude of an impact • Frequency of impacts • Magnitude and Frequency are inversely related • Large magnitude events occur less frequently • Large magnitude events have a lower probability of recurring in any given time interval

16. The "Golden Mean" • Most of the work of forming Earth's surface is done by events of moderate magnitude and frequency • "Bankfull" Floods • Normal Wave Base in Nearshore Zone • Mid-latitude Cyclone Storms

17. Natural Hazard Impacts Direct Effects include people killed, injured, dislocated, or otherwise damaged Indirect Effects include • emotional distress • donations of money and goods • financial disruption and funding of recovery

18. Disaster Recovery Stages of Disaster Recovery: • Emergency Work • Restoration of Services and Communication Lines • Reconstruction

19. Figure 1.16

20. Human Dimension • Human Interaction with Natural Hazards increases with population density • Some technologies play a specific role in triggering or mitigating disasters and catastrophes caused by natural hazards • Human Interaction with Natural Hazards is discussed in each chapter of your textbook (Sections 2.8, 3.6, 4.6, etc...) • Risk Assessment is important to understanding the effects of natural hazards • Minimizing the Risk from Natural Hazards is discussed in each chapter of your textbook (Sections 3.9, 4.6, 5.7, etc...)

21. Natural Hazard Linkages • Earthquakes produce • landslides • tsunamis • Hurricanes cause • flooding • coastal erosion • Volcanic eruptions cause • lahars (catastrophic floods laden with ashy mud) • weather and even climate changes downwind

22. Natural Hazard Linkages • Hurricanes (Katrina) • high winds damage property and harm people directly • flooding that follows storm does more damage, for which landowners may not be insured • coastal flooding is linked to other coastal processes • tropical storm intensity may increase in warmer climate due to sea surface temperatures • Earthquakes (Pakistan) and Volcanoes (Nevado del Ruiz) • represent plate tectonic movements and in turn trigger landslides, floods, tsunamis,....

23. Natural Service Functions • "Ecosystem" services are benefits to humankind which result from resources and processes supplied by natural ecosystems: • provisioning such as production of food and water • regulatingsuch as control of climate and disease • supporting such as nutrient cycles and crop pollination • cultural such as spiritual and recreational benefits • preserving such as maintenance of biodiversity • Natural Service Functions of Natural Hazards are discussed in each chapter of your textbook (Sections 2.7, 3.5, 4.5, etc...)