Natural Disasters Lecture 1 (Introduction)

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Terminology and basic concepts for a GE-level course in natural disasters.


1. Introduction to Natural Disasters 2. HazardA condition that threatens human life or propertyPhoto by W. W.Little 3. DisasterAn event that results in loss ofproperty or life that exceeds thecapacity of the community torespond. 4. CatastropheA large-scale disaster that results in massive loss of life and propertythat has long-term societal (economic, political) impacts. 5. NaturalA process, condition, event, or item not controlled or influenced byhuman activity. 6. Common Natural DisastersEarthquakes Volcanoes Tsunamis LandslidesHurricanes Tornadoes Blizzards Dust StormsFloods Droughts Wildfires Sink Holes 7. Linked EventsRock avalanche caused byearthquake (Yungay, Peru).Lahar caused by volcaniceruption (Mt. St. Helens).One type of event can trigger a different type of event. 8. Magnitude (Energy)Richter Scale for earthquakes Volcanic Explosivity IndexEnhanced Saffir-Simpson Scale for hurricanes Fujita Scale for tornadoesRefers to the size of an event as measured by a defined scale. 9. Frequency (Recurrence Interval)Refers to how often a type and size of event is repeated. Variesgreatly by nature of event and by local conditions; therefore,determined on a local and regional basis using broad averages. 10. Magnitude vs. FrequencyThere is an inversely proportional relationship between disastermagnitude (released energy) and frequency. 11. Is the Number of NaturalHazards/Disasters/CatastrophiesIncreasing?The many eruptions, earthquakes and tidal waves which haveoccurred...are signs which the Savior declared would foreshadowhis second coming... The wise and prudent will heed the warningand prepare themselves that they be not taken unawares.Joseph F. Smith (Messages of the First Presidency, 4:132) 12. News Scientist, 16 January 2012Depends on Time Frame 13. Population ImpactGlobal Population ChangeGlobal Population DistributionGlobal Flood Hazard Map 14. Population Impact: Nevado del Ruiz 1845: Volcanic eruption triggers a lahar killing ~1,000 people. 1845 1985: Population increases due to fertile volcanic farm land. 1985: Volcanic eruption triggers a lahar killing ~21,000 people. 15. Urbanization ImpactManmade features can both exacerbate and mitigate the impactof natural hazards. 16. MitigationEfforts to reduce consequences of natural processes or events. 17. Prior HistoryMost natural processes have a somewhat regular recurrenceinterval, allowing a very general predictability based mostly ona statistical probability of occurrence over a broad span of time. 18. Recognition of PrecursorsConditions or occurrences that precede a disaster, providingwarning that an event is likely. Not all events have precursors. 19. Warning SystemsSirens for flash floods, tornadoes,and mass wasting.Buoys for tsunamis.First-motion dectectors for earthquakes.News media for hurricanes, blizzards,and regional flooding. 20. Risk Analysis (Hazard) MapsBased on past history of a locality and comparison with similarlocalities, maps can be produced that show the potential risk forspecific types and magnitudes of geological and hydrological events. 21. Generalized Hazard Maps for the U.S.Earthquakes Volcanism Mass WastingHurricanesFloods 22. Engineering AdvancesKashmir, Pakistan 2005, Mw 7.6Vina del Mar, Chili 2010, Mw 8.8 23. Retrofitting StructuresSome historical structures are retrofitted to mitigate earthquakedamage while maintaining original character. 24. Federal Relief SpendingWhat is the role of the federal, state, and local governments, ofinsurance companies, and of personal responsibility? 25. Best Advice: Be PreparedThe prudent see danger and take refuge, but thesimple keep going and suffer for it.Proverbs 27:12Too often we bask in our comfortable complacency and rationalize that the ravages of war, economicdisaster, famine, and earthquake cannot happen here. Those who believe this are either not acquaintedwith the revelations of the Lord, or they do not believe them. Those who smugly think these calamitieswill not happen, that they somehow will be set aside because of the righteousness of the Saints, aredeceived and will rue the day they harbored such a delusion.Ezra Taft Benson, Prepare for the Days of Tribulation,Ensign, Nov 1980, 32In mercy the Lord warns and forewarns. He sees the coming storm, knows the forces operating to produceit, and calls aloud through His prophets, advises, counsels, exhorts, even commands that we prepare forwhat is about to befall and take shelter while yet there is time. But we go our several ways, feasting andmaking merry, consoling conscience with the easy fancy of time enough and in idle hope that the tempestwill pass us by, or that, when it begins to gather thick and black about us we can turn back and findshelter.James E Talmage, The Parables of James E. Talmage, p. 50 26. Mitigation ImpactThough the number of people affected and the cost of naturaldisasters has increased in recent decades, the number ofdeaths have decreased. 27. Most Costly Events: 1980-2011 28. Most Deadly Events: 1980-2011 29. All-time Most Deadly Events


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