Chapter 1 Natural Hazards and Disasters What is a Natural Disaster A natural hazard is a natural process that poses a threat to property and human life Natural disasters occur when the earth s natural processes concentrate energy and then release it causing property damage and or loss of life Natural Processes or Natural Disasters The earth is a dynamic planet with complex internal and external flows of energy that produce natural processes that are supposed to happen and have been for billions of years Natural processes become natural disasters or catastrophes when they adversely affect humans and their property Public Awareness and Avoiding Natural Disasters We may not recognize the signs of imminent catastrophes because these events are infrequent There are numerous small events fewer larger events and only rarely a giant event Most people do not realize the inherent danger of an unusual occurrence Forget Lack of knowledge Irrational It won t happen here or it won t happen to me Living in the Idiot Zone Cultural Economic Reasons o Productive agricultural soil o Inexpensive land o Natural transportation corridors Frivolous Reasons o Scenic Environments Population Growth Population Growth As the growth of the world s population accelerates more and more people find themselves living in close proximity to Earth s most hazardous places Human population has grown exponentially doubling about every 50 to 100 years Since the 1950 s the world population has doubled to 6 billion and is expected to reach 10 to 15 billion by 2050 What is the Correlation between Population Density and Natural Disaster Deaths Where humans are concentrated high energy events kill more people In past 32 years 86 of natural disaster deaths have occurred in Asia Disasters cost money and lives wherever they occur but developed countries almost always lose more money while underdeveloped countries lose more lives Not Just High Population Density Poor warning and preparedness systems Poor evacuation plans Poorly constructed buildings or inappropriately constructed buildings Poor disaster relief plans Role of the U S Government Conducts and sponsors research into the nature and behavior of natural disasters Prediction USGS National Weather Service Mitigation Army Corps of Engineers Response FEMA Predicting Catastrophe Disaster Prediction The more predictable the event the fewer the lives lost Location Certain events are known to occur in certain areas Forecasting Warning Based on linear projections of past experiences forecasts can be made which indicate that a future hazardous event will occur in a certain area within a given span of time often decades with an approximate percentage probability Recurrence Interval Statistical prediction based past data over a long period of time Defined as the expected time interval between a hazard of a given magnitude It is a statistical probability that a natural event of a particular size will happen within a certain period of time Attempts to predict when a natural disaster of a given magnitude most likely will occur Estimations of recurrence intervals are made by plotting a graph of each event size versus the time interval between sequential individual events Plotting on a logarithmic scale leads to a straight line graph that can be extrapolated to values larger than those in the historic record Magnitude the amount of energy released or how much power Frequency the recurrence interval or how often events of a given magnitude occur or are expected to occur This relationship is inversely proportional where small magnitude events occur frequently and large scale magnitude events are infrequent Precursor Events Some natural disasters are directly related to or the direct consequence of another event Sometimes major natural disasters are preceded by a series of smaller precursor events which may warn of the impending disaster Anticipatory Hazard Management Risk Assessment and deliberate adjustment to minimize impact of natural hazards Considers the residents environmental awareness perception of the problem and fiscal restraints Choosing to do nothing It is hard to persuade people to expend time and money to prevent disaster that does not appear imminent and in their minds might never happen Mitigation Mitigation refers to efforts to prepare for disaster and reduce its damage and can include government policy engineering projects and public education Land Use Planning Restrictive zoning abandonment and public use of hazardous areas An obvious way to avoid catastrophe but often difficult to impose Many hazardous areas are already heavily populated Poses an infringement on property rights Bad for economic growth and development Government policy encourages future damage from natural hazards Federal Disaster Assistance Multi million dollar mitigation projects Government subsidy to rebuild in hazardous areas Engineering Solutions The most common human reaction to a current or potential catastrophe Typically involves modifying the natural environment in and attempt to control nature Engineering structures often create disasters that are anthropogenic in origin a result of humans interacting with the natural environment Transfer the problem elsewhere To someone else To a later point in time Risk Assessment Risk is essentially a hazard considered in light of its recurrence interval and expected cost The greater the hazard and the shorter its recurrence interval the greater the risk Risk probability of occurrence x probable cost of losses Most widely used in the insurance industry in establishing premium rates for policies Insurance is generally available for events that present relatively little risk Mandated insurance by a consortium of insurance companies in high risk areas Hazard Warning Systems and Evacuation Procedures The Emergency Alert System EAS is a national system in the U S used for state and local emergencies The EAS covers both radio and television Established Evacuation Routes Established Shelters and Emergency Housing Hazard Management Reactive Response Emergency Response First Responders members of emergency communications centers ECCs emergency medical services EMS fire and rescue services law enforcement agencies hospitals Local and State Offices and Agencies of Emergency Management The Federal Emergency Management Agency is tasked with planning for responding to and recovering from disasters FEMA provides state and local governments with personnel technical
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