EOSC 114 - Natural Disasters - All Chapters on Exam

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Earth and Ocean Sciences
EOSC 114
Stuart Sutherland

September 2010Elaine Jessica GiangCh 1 intro to natural hazardsMost tsunamis are triggered at SUBDUCTION ZONESlong narrow strips of Earths lithosphere outermost layer containing the crust and upper mantle where one tectonic plate moves beneath another2 tsunami warning signs 1 Strong groundshaking close to the epicenter2A rapid withdrawal of the sea to very low levelsDening and minimizing disastersNatural hazards are caused by both internal from inside Earth and external processes from the sun PROCESSES are the ways in which events affect the surface of the Earth HAZARDany natural process that threatens human life or propertyRISKthe probability of a hazardous event times the expected damageDISASTERCATASTROPHEevents that cause serious injury loss of life and property damage in a brief amount of time over a specic area catastrophe tends to be more severe and takes longer to recover from MITIGATIONefforts to prepare for disasters to minimize their effectsWhat we can do to minimize impact of disasters Improve existing warning systems and install new onesImprove communication infrastructure and chainofcommand protocol so emergency officials in coastal communities are warned ASAPPublic education programwhere to go where to take how to get intoEvacuation routes should be publicizedmarked by signsRole of time in understanding hazardsHazards are recurrent events Thus by combining our knowledge of a history of past events with a surveying of geologic features created by the past disasters our hazard forecasts and warnings will become more accurateThe geologic cycleThe 4 associated sequences of the Earth processes that produce the minerals fuels land water and atmosphere needed for survival through physical chemical and biological forcesThey are all include a renewal process are driven by energy and are cyclic They do not all relate to the movement of the Earths crust The tectonic cycleThe creation movement and destruction of tectonic platesOceanic plates are denser than continental plates and thus will always move underneath continental platesDIVERGENT BOUNDARIES two plates pulling away from each other If its in the ocean then it is known as SEAFLOOR SPREADING where magma comes up to create new crust CONVERGENT BOUNDARIES two plates collide into each other usually resulting in a subduction zone If an oceanic plate goes under a continental plate then the oceanic plate heats up as it moves under and releases gases that melt the lower crustal rocks Magma moves up slowly until it reaches the surface and erupts building volcanoesColliding plates with similar density usually produces mountains Ocean platesolder one subducts younger oneSeptember 2010Elaine Jessica GiangSUBDUCTION adds material to continents sedimentsrockcrustal fragments on the subducting plate are added to the continentTRANSFORM sheartransverse BOUNDARY two plates slide horizontally past each other HOTSPOTS an almost stationary source of heat within the mantle mantle is just below crust that produces volcanoes at specic xed points of Earths surface as plates move over itThe rock cycleThe recycling of 3 major groups of rocks it is driven by energy from the core and sunIGNEOUS ROCK crystallization of molten rockSEDIMENTARY ROCK sediment is produced as rocks atnear the surface break down chemically and physically WEATHERING LITHIFICATION then compacts and cements these sediments into sedimentary rockMETAMORPHIC ROCK the morphing of rock by chemical uids pressure or heat naturally occurring agentsIf sedimentary rock is buried deep enough it will melt and thus the potential for the cycle to start all over again is renewedThe hydrologic cycleThe cycling of water form the oceans to the atmosphere continents and islands and back to the oceans It is driven by solar energy and by evaporation precipitation surface runoff and subsurface owRESIDENCE TIME avg amount of time that a drop of water spends in any one compartment Biogeochemical cyclesThe transfers of cycling of elements through the atmosphere lithosphere hydrosphere and biosphere it is intimately related to the other cyclestectonic provides water gases heat and energy for transferring dissolved solids in gases aerosols and solutionsThe other cycles transfer and store chemical elements by a series of compartmentsreservoirs water soil and rockFundamental concepts for understanding natural hazards1Hazards can be predicted through scientic analysis most can be predicted from a history of similar events patterns in their occurrences and by warning events that precede them2Risk analysis is an important part of understanding the effects of a hazard you can use risk analysis to assess the probability that a hazard will occur and what its severity will beThis helps people decide whether or not living in a hazard prone area is worth the risk3Natural hazards are linked together and to the physical environment one hazard will often produce another Ie Loose rocks are more prone to landslides than granite4Damage from natural disasters is increasing due to population growth property development in dangerous areas and poor landuse practices Higher magnitude events occur less often and lower magnitude events occur a lot inverse relationship5Damage from disasters can be minimized by using science good landuse planning and regulation engineering and being prepared and proactive
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