Our hazardous environment geog 1110 dr thieme
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Our Hazardous Environment GEOG 1110 Dr. Thieme. Scientific Method, Forecasts, Prediction, and Risk Assessment. Scientific Method. make observations. formulate a hypothesis. test the hypothesis with new observations. draw conclusions (build a "theory"). Scientific Hypothesis.

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Our Hazardous Environment GEOG 1110 Dr. Thieme

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Our hazardous environment geog 1110 dr thieme

Our Hazardous EnvironmentGEOG 1110Dr. Thieme

Scientific Method, Forecasts, Prediction, and Risk Assessment


Scientific method

Scientific Method

  • make observations

  • formulate a hypothesis

  • test the hypothesis with new observations

  • draw conclusions (build a "theory")


Scientific hypothesis

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


Our hazardous environment geog 1110 dr thieme

  • Observation: A landslide occurred and destroyed three homes

  • Hypothesis:Water on the hillslope, seeping from a buried waterline, caused the landslide


Risk assessment

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


Our hazardous environment geog 1110 dr thieme

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....


Risk analysis

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)


Risk analysis1

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


Risk analysis and planning

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


Avoiding disasters

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


Our hazardous environment geog 1110 dr thieme

Flow Path for Predicting or Warning about a Natural Disaster


Prediction and forecast

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


Precursor events

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


Natural hazard impacts

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


The golden mean

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


Natural hazard impacts1

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


Disaster recovery

Disaster Recovery

Stages of Disaster Recovery:

  • Emergency Work

  • Restoration of Services and Communication Lines

  • Reconstruction


Figure 1 16

Figure 1.16


Human dimension

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...)


Natural hazard linkages

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


Natural hazard linkages1

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,....


Natural service functions

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...)


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