Natural Hazards and Disasters Premise of the course is to provide a basic understanding of how earth processes give rise to disasters and how people interact with these hazardous processes 1 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 Refer to page 3 2 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 Refer to page 3 3 Some of the Natural Disasters Studied in this Course Earthquakes Tsunami Volcanoes Landslides Tornadoes Hurricanes Floods 4 Public Awareness and Avoiding Natural Disasters Most people do 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 Forget Lack of knowledge Irrational It won t happen here or it won t happen to me Refer to page 9 10 5 Living in the Idiot Zone Cultural Economic Reasons Productive agricultural soil Inexpensive land Natural transportation corridors Frivolous Reasons Scenic Environments Population Growth Refer to page 9 10 6 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 Refer to page 3 4 7 Top 10 Deadliest Natural Disasters 1970 2001 400 000 14 Nov 1970 Hurricane 250 000 28 Jul 1976 Earthquake China 140 000 30 Apr 1991 Hurricane Bangladesh 60 000 31 May 1970Landslide Peru 50 000 15 Dec 1999 Flooding Venezuela 50 000 21 Jun 1990 Earthquake Iran 25 000 7 Dec 1988 Earthquake Armenia 25 000 16 Sep 1978 Earthquake Iran 23 000 13 Nov 1985 Mudflow 22 000 4 Feb 1976 Earthquake Guatemala Bangladesh Columbia 8 Earthquakes Tornadoes Which two Volcanoes natural processes cause Tsunami the most deaths Hurricanes Floods Landslides 9 From 19702001 21 out of 40 of the Earth s worst disasters were earthquakes 9 out of 40 were hurricanes 9 hurricanes killed 599 544 people 21 earthquakes killed 571 146 people 10 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 Regional population patterns Population density Consortium for International Earth Science Information Network 11 Fatalities from Natural Disasters Worldwide from 1947 1980 12 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 Refer to page 3 13 U S Economic and Insured Losses from Natural Disasters 1950 2000 Refer to page 3 4 14 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 Refer to page 8 9 15 Predicting Catastrophe Disaster Prediction The more predictable the event the fewer the lives lost Location Certain events are known to occur in certain areas Refer to page 3 5 16 Predicting Catastrophe Location Global Distribution of Active Earthquakes 17 Predicting Catastrophe Location Global Distribution of Active Volcanoes 18 Predicting Catastrophe Location Global Hurricane Distribution 19 Predicting Catastrophe 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 Refer to page 3 5 20 Predicting Catastrophe 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 Refer to page 3 5 Predicting Catastrophe Recurrence Interval 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 Refer to page 3 5 22 Predicting Catastrophe Recurrence Interval 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 Refer to page 3 6 23 Predicting Catastrophe 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 Refer to page 6 7 24 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 25 Anticipatory Hazard Management 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 26 Anticipatory Hazard Management 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
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