八年级下册英语Natural disaster.docx

八年级下册英语Natural disaster.docx

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八年级下册英语Naturaldisaster

Naturaldisaster

Anaturaldisasteristheeffectofanaturalhazard（e.g.flood,volcaniceruption,earthquake,orlandslide）thataffectstheenvironment,andleadstofinancial,environmentalorhumanlosses.Theresultinglossdependsonthecapacityofthepopulationtosupportorresistthedisaster,andtheirresilience.[1]Thisunderstandingisconcentratedintheformulation:

"disastersoccurwhenhazardsmeetvulnerability."[2]Anaturalhazardwillhenceneverresultinanaturaldisasterinareaswithoutvulnerability,e.g.strongearthquakesinuninhabitedareas.Thetermnaturalhasconsequentlybeendisputedbecausetheeventssimplyarenothazardsordisasterswithouthumaninvolvement.[3]

Naturalhazards

Mainarticle:

Naturalhazard

Anaturalhazardisathreatofaneventthatwillhaveanegativeeffectonpeopleortheenvironment.Manynaturalhazardsarerelated,e.g.earthquakescanresultintsunamis,droughtcanleaddirectlytofamineanddisease.Aconcreteexampleofthedivisionbetweenhazardanddisasteristhatthe1906SanFranciscoearthquakewasadisaster,whereasearthquakesareahazard.Hazardsareconsequentlyrelatingtoafutureoccurrenceanddisasterstopastorcurrentoccurrences....

Naturaldisasters

Mainarticles:

disasterandlistofdeadliestnaturaldisasters

Lossofdignity

In1994JoeMurfinlosthisdignity

Landmovementdisasters

Avalanches

Avalancheonthebackside（East）ofMt.Timpanogos,UtahatAspenGrovetrail

Notableavalanchesinclude:

∙The1910Wellingtonavalanche

∙The1954Blonsavalanches

∙The1970Ancashearthquake

∙The1999GaltürAvalanche

∙The2002Kolka-Karmadonrockiceslide

Earthquakes

AnEarthquakeisasuddenshakingorvibrationoftheEarth'scrust.Thevibrationsmayvaryinmagnitude.Theearthquakehaspointoforiginundergroundcalledthe"focus".Thepointdirectlyabovethefocusonthesurfaceiscalledthe"epicentre".Earthquakesbythemselvesrarelykillpeopleorwildlife.Itisusuallythesecondaryeventsthattheytrigger,suchasbuildingcollapse,fires,tsunamisandvolcanoes,thatareactuallythehumandisaster.Asmanyofthesecouldbeavoidedbybetterconstruction,safetysystems,earlywarningandevacuationplanning,thetermunnaturaldisasterisnotunwarranted.

Earthquakesarecausedbythedischargeofstressaccumulatedalonggeologicfaults.

Mainarticle:

Listofearthquakes

Someofthemostsignificantearthquakesinrecenttimesinclude:

∙The2004IndianOceanearthquake,thesecondlargestearthquakeinrecordedhistory,registeringamomentmagnitudeof9.3.Thehugetsunamistriggeredbythisearthquakecostthelivesofatleast229,000people.

∙The7.6-7.72005Kashmirearthquake,whichcost79,000livesinPakistan.

∙The7.7magnitudeJuly2006Javaearthquake,whichalsotriggeredtsunamis.

ASumatranvillage,devastatedbythetsunamithatfollowedthe2004IndianOceanearthquake

∙The7.9magnitudeMay12,2008SichuanearthquakeinSichuanProvince,China.Deathtollatover61,150asofMay27,2008.

Lahars

Alaharisavolcanicmudfloworlandslide.The1953Tangiwaidisasterwascausedbyalahar,aswasthe1985ArmerotragedyinwhichthetownofArmerowasburiedandanestimated23,000peoplewerekilled.

LandslidesandMudflows

TheseoccurwithsomeregularityinpartsofCaliforniaafterperiodsofheavyrain.

Volcaniceruptions

Pu'u'Ō'ō

∙AnEruptionmayinitselfbeadisasterduetotheexplosionofthevolcanoorthefallofrockbutthereareseveraleffectsthatmayhappenafteraneruptionthatarealsohazardoustohumanlife.

∙Lavamaybeproducedduringtheeruptionofavolcanoamaterialconsistingofsuperheatedrock.Thereareseveraldifferentformswhichmaybeeithercrumblyorgluey.Leavingthevolcanothisdestroysanybuildingsandplantsitencounters.

∙Volcanicash-generallymeaningthecooledash-mayformacloud,andsettlethicklyinnearbylocations.Whenmixedwithwaterthisformsaconcretelikematerial.Insufficientquantityashmaycauseroofstocollapseunderitsweightbutevensmallquantitieswillcauseillhealthifinhaled.Sincetheashhastheconsistencyofgroundglassitcausesabrasiondamagetomovingpartssuchasengines.

∙Supervolcanos :

AccordingtotheTobacatastrophetheory70to75thousandyearsagoasupervolcaniceventatLakeTobareducedthehumanpopulationto10,000oreven1,000breedingpairscreatingabottleneckinhumanevolution.Themaindangerfromasupervolcanoistheimmensecloudofashwhichhasadisastrousglobaleffectonclimateandtemperatureformanyyears.

∙Pyroclasticflowsconsistofacloudofhotvolcanicashwhichbuildsupintheairaboveavolcanountilitcollapsesunderitsownweightandstreamsveryrapidlyfromthemountainburninganythinginitspath.ItisbelievedthatPompeiiwasdestroyedbyapyroclasticflow.

Waterdisasters

Floods

Mainarticle:

Listoffloods

TheLimpopoRiver,insouthernMozambique,duringthe2000Mozambiqueflood

Someofthemostnotablefloodsinclude:

∙TheHuangHe（YellowRiver）inChinafloodsparticularlyoften.TheGreatFloodof1931causedbetween800,000and4,000,000deaths.

∙TheGreatFloodof1993wasoneofthemostcostlyfloodsinUnitedStateshistory.

∙The1998YangtzeRiverFloods,alsoinChina,left14millionpeoplehomeless.

∙The2000Mozambiquefloodcoveredmuchofthecountryforthreeweeks,resultinginthousandsofdeaths,andleavingthecountrydevastatedforyearsafterward.

Tropicalcyclonescanresultinextensivefloodingandstormsurge,ashappenedwith:

∙BholaCyclone,strikingEastPakistan（nowBangladesh）in1970,

∙TyphoonNina,strikingChinain1975,

∙TropicalStormAllison,whichstruckHouston,Texasin2001and

∙HurricaneKatrina,whichleftmostofNewOrleansunderwaterin2005.Muchofthefloodingwasduetothefailureofthecity'sleveesystem.

Limniceruptions

AcowsuffocatedbygasesfromLakeNyosafteralimniceruption

AlimniceruptionoccurswhenCO2suddenlyeruptsfromdeeplakewater,posingthethreatofsuffocatingwildlife,livestockandhumans.SuchaneruptionmayalsocausetsunamisinthelakeastherisingCO2displaceswater.Scientistsbelievelandslides,volcanicactivity,orexplosionscantriggersuchaneruption.Todate,onlytwolimniceruptionshavebeenobservedandrecorded:

∙In1984,inCameroon,alimniceruptioninLakeMonouncausedthedeathsof37nearbyresidents

∙AtnearbyLakeNyosin1986amuchlargereruptionkilledbetween1,700and1,800peoplebyasphyxiation.

Tsunamis

ThetsunamicausedbytheDecember26,2004earthquakestrikesAoNang,Thailand.

TsunamicanbecausedbyunderseaearthquakesastheonecausedinAoNang,Thailandbythe2004IndianOceanEarthquake,orbylandslidessuchastheonewhichoccurredatLituyaBay,Alaskain.

∙AoNang,Thailand（2004）.The2004IndianOceanEarthquakecreatedtheBoxingDayTsunamianddisasteratthissite.

∙LituyaBay,Alaska（1953）.Amega-tsunamioccurredhere,thelargesteverrecorded.

∙ThiswouldalsofitwithinLandmovementcategorybecauseitstartswithanearthquake.

Weatherdisasters

Mainarticle:

Weatherdisasters

Youngsteerafterablizzard,March1966

Blizzards

SignificantblizzardsintheUnitedStatesinclude:

∙TheGreatBlizzardof1888

∙TheSchoolhouseBlizzardearlierthesameyear

∙TheArmisticeDayBlizzardin1940

∙TheStormoftheCenturyin1993

Cyclonicstorms

Mainarticles:

tropicalcycloneandcyclone

Cyclone,tropicalcyclone,hurricane,andtyphoonaredifferentnamesforthesamephenomenonacyclonicstormsystemthatformsovertheoceans.Thedeadliesthurricaneeverwasthe1970BholacyclonethedeadliestAtlantichurricanewastheGreatHurricaneof1780whichdevastatedMartiniqueSt.EustatiusandBarbados.AnothernotablehurricaneisHurricaneKatrinawhichdevastatedtheGulfCoastoftheUnitedStatesin2005.

Droughts

Well-knownhistoricaldroughtsinclude:

∙1900Indiakillingbetween250,000and3.25million.

∙1921-22SovietUnioninwhichover5millionperishedfromstarvationduetodrought

∙1928-30northwestChinaresultinginover3milliondeathsbyfamine.

∙1936and1941SichuanProvinceChinaresultingin5millionand2.5milliondeathsrespectively.

∙Asof2006WesternAustraliaNewSouthWalesVictoriaAustraliaVictoriaandQueenslandstatesofAustraliahavebeenunderdroughtconditionsforfivetotenyears.Thedroughtisbeginningtoaffecturbanareapopulationsforthefirsttime.

∙In2006SichuanProvinceChinaexperienceditsworstdroughtinmoderntimeswithnearly8millionpeopleandover7millioncattlefacingwatershortages.

Hailstorms

AparticularlydamaginghailstormhitMunich,GermanyonAugust31,1986,fellingthousandsoftreesandcausingmillionsofdollarsininsuranceclaims.

Heatwaves

TheworstheatwaveinrecenthistorywastheEuropeanHeatWaveof2003.

HurricaneKatrina

Tornadoes

Mainarticle:

tornado

Fire

Mainarticle:

Listofforestfires

Wildfiresareanuncontrolledfireburninginwildlandareas.Commoncausesincludelightninganddroughtbutwildfiresmayalsobestartedbyhumannegligenceorarson.Theycanbeathreattothoseinruralareasandalsowildlife.

Healthanddisease

Epidemic

Mainarticle:

Listofepidemics

TheAH5N1virus,whichcausesAvianinfluenza

Anepidemicisanoutbreakofacontractiblediseasethatspreadsatarapidratethroughahumanpopulation.Apandemicisanepidemicwhosespreadisglobal.Therehavebeenmanyepidemicsthroughouthistory,suchasBlackDeath.Inthelasthundredyears,significantpandemicsinclude:

∙The1918Spanishflupandemic,killing