Our Hazardous Environment GEOG 1110 Dr. Thieme

1 / 25

# Our Hazardous Environment GEOG 1110 Dr. Thieme - PowerPoint PPT Presentation

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.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about 'Our Hazardous Environment GEOG 1110 Dr. Thieme' - marnie

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

### Our Hazardous EnvironmentGEOG 1110Dr. 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
• 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
Observation: A landslide occurred and destroyed three homes
• Hypothesis:Water on the hillslope, seeping from a buried waterline, caused the landslide
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
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
• 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 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
• 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
• 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
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
• 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
• 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"
• 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 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

Stages of Disaster Recovery:

• Emergency Work
• Restoration of Services and Communication Lines
• Reconstruction
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...)
• 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
• 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
• "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...)