ES 140 Natural Disasters Book Notes

ES 140 Natural Disasters Book Notes - ES 140 Natural...

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Chapter 1 Pakistan Earthquake October 8, 2005 – deadliest 05 disasters. Earth shook violently for 50 seconds about 10 km (6mi) north of Muzaffarabad. 88,000 died. Hurricane Katrina August 29, 2005 – New Orleans. $135 billion in damages. Great Natural Disasters Events that so overwhelm regions that international assistance is needed to rescue and care for people, clean up the destruction and beginning the process of reconstructions. IN the last 56 years, 274 GND have occurred. Biggest killers worldwide in a 36 year period have been hurricanes and earthquakes and water related phenomena i.e. severe weather and floods killed more people than volcanoes and landslides. Human Responses to Disaster Increase in suicides and increase in altruism. Natural Hazards Natural Hazards – May be assessed as the probability of occurrence of a dangerous event. I.e. people building a home next to a river that will flood. There may not be a disaster for years, but the hazard remains. Natural Hazards are inevitable but natural disasters are not. Process of Mitigations – Making plans and taking actions to eliminate or reduce the threat of future death and destruction when natural hazards suddenly become great threats. Some actions may be engineering, physical, social and political Mitigation is also needed after great disasters because people around the world tend to reoccupy the same site after a disastrous event is done. I earthquake knock down cities and survivors come back and rebuild on the site. Magnitude, Frequency and Return Period Earth is dynamic. Constant energy fueled events are common but their magnitudes vary markedly over space and time. Magnitude - An assessment of the size of an event. Magnitude scales exist for earthquakes, volcanic eruptions, hurricanes and tornadoes. For earthquakes, different magnitudes are calculated for the same earthquake when different types of seismic waves are used. Concentrated pulses of energy are the cause of natural disasters. In general, there is an inverse correlation between the frequency and the magnitude of a process. Frequent occurrences are low in magnitude, involving little energy in each event. As magnitude of an event increases, its frequency of occurrence decreases. Another way to understand how frequently the truly large events occurs is to match a given magnitude event with its return period Return Period – Or recurrence interval, is the number of years between same sized events. In general, the larger and more energetic the event, the longer the return period. Double time (in years) = 70/% growth rate per year Human Population Today World population grows at about 1.2% per year for a doubling time of 58 years. 1.2% gain is a net figure derived by measuring the birth rate and subtracting the death rate.
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This note was uploaded on 09/01/2011 for the course CAS ES 140 taught by Professor Fitzgereld during the Spring '07 term at BU.

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ES 140 Natural Disasters Book Notes - ES 140 Natural...

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