NATURALDISASTER---EARTHQUAKETherearemanynaturaldisastersintheworld.Earthquakesareoneofthemostdangerous,overamillionearthquakesoccurseachyear.Althoughsomearetoosmalltobenoticed,othersmaycausedamages,deathanddestruction.EarthquakesarecausedbythemovementoftheEarth'scrust.Thecrustismadeupofplatesfloatingonmantle.Whentwoplatespushagainsteachother,itcausesearthquakeswhichmaydestroystownsorformnewclimates.Ifanearthquakehappensundertheseaandcauseshugewaves,itiscalleda"tsunami".Atsunamicansweepacrossoceansatthespeedof800kilometersperhour.Whenanearthquakehappensoutintheopenseas,thewavecanonlybeabout1meterhigh,butwhenitmeetsland,itmaygrowupto30metershighandcanleadtoenormousdamage.Forinstance,aharboronOkushiriIsland,Japan,wasdestroyedbyatsunamiin1993.Whenanearthquakehappensonland,itmaycausemoredamagetobuildings,harm,anddeathtohumans.Describedbelowishowanearthquakeusuallyhappens:1.Barelyfeltbuthangingobjectsmayswing.2.Feltbyallandwindowsshatterandbuildingscollapse.3.Seriousdamage,cracksopenintheground.4.Maycausedeath,andlandscapechanges.用心爱心专心TheSanAndreasFaultinCaliforniaisoneofthebiggestfaultlinesintheworld.Faultlinesarealongtheedgeofamovingplate.Mostearthquakeshappenatfaultlines.Thisishowandwhatanearthquakedoes.Atfirst,thefocus(centre)ofanearthquakesendsoutshockwavesalongfaultlinesthroughlayersofrocks.Onland,itcausesdamagetobuildings.AnearthquakewhichstruckTurkeywasquitelarge,manypeoplediedandmanybuildingsweredestroyed.AnotherearthquakehappenedinTaiwan.TheearthquakeinTaiwanwasbiggerthantheearthquakeinTurkeybutfewerpeopledied;itwasstrange.AnotheronewasinMexicoanditwasaftertheearthquakeinTaiwan.TheRescueTeamdoesn'tknowexactlyhowmanypeopledied.Ithappenedintheoceansoitwasnottoobad.Itwasabout7pointsomethingontheRichterscalewedon'tknowexactly.Earthquakesmaycausevolcaniceruptions,andthatmakesthedisasterworsebecausepeoplehavetoruntoanopenspaceandhidefromthevolcanotoo.Somemayevencausefiresfromthedamagedkitchens.Scientistsusethe"RichterScale"tomeasurehowbiganearthquakeisandtrytobereadyforanearthquakebuttheydidn'tknowhowtoyet.Thereareearthquake-proofbuildings.Earthquake-proofbuildingsarebuiltonrubberspringssowhenanearthquakecome,itwillswaygentlyandpeoplewillbesafeinside.Otherbuildingsbreakapartandinside,peopleareinjuredorharmed.Insomeschools,theyteachwhattodoinanearthquake.Scientistsarealsolearningaboutearthquakes.Theystudyequipmentonearthquakesandmanyotherthings.Theystudyequipmentthatmeasuresmovementsinrocksbuttheydon'talwaysgetitright.Whenabigearthquakecame,theonlygoodthingfromitisthatitchangeslandscapes,sowecanhavenewdifferentlandscapethatwewillnevergetusedto;however,welosemanypeopleandmuchpropertyunfortunately.Earthquakesarenaturaldisastersandcannotbecontrolledby用心爱心专心humanbeingsnowbutmaybeintheunknownfuture.用心爱心专心
