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")

3
(No Transcript)
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 or null 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
• regulating such 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...)

24
(No Transcript)
25
(No Transcript)