英语翻译EarthquakesAnearthquakeiscausedbyasuddensliponafault.Afaultisafractureoftheearthalongwhichrocksononesidehavemovedrelativetothoseontheotherside.Stressesintheearth'souterlayerpushthesidesofthefault

　　英语翻译

　　Earthquakes

　　Anearthquakeiscausedbyasuddensliponafault.Afaultisafractureoftheearthalongwhichrocksononesidehavemovedrelativetothoseontheotherside.Stressesintheearth'souterlayerpushthesidesofthefaulttogether.Afterthestressesaccumulateovertime,therocksslipssuddenly,releasingenergyinwavesthattravelthroughtherocktocausetheshakingthatwefeelduringanearthquake.Earthquaketendtobeconcentratedattheboundariesoftheplates.Thereare7majorcrustalplatesonearth,about80km(50miles)thick,allinconstantmotionrelativetooneanother.Theymoveatbetween10mmand130mmperyear.Itisestimatedthatthereareseveralmillionearthquakesintheworldeachyear.Manyoftheseeqrthquakesgoundetectedbecausetheyoccurinremoteareasorhaveverysmallmagnitudes.Onaverage,about60earthquakesperyearareclassifiedassignificant,with19classifiedasmajor.Asignificantearthquakesisoneofmagnitude6.5orhigheroroneoflessermagnitudethatcausescasualtiesorconsiderabledamage.Majorearthquakeshaveamagnitudelargerthan7.0.TheGreatTangshanEarthquakeofJuly28,1976isoneofthelargestearthquakes.Manysourceslistitas8.2ontheRichterscale,butChineseGovernment'sofficialsourcesstate7.8or7.6.The2004IndianOceanEarthquakewasanunderseaearthquakesthatoccurredonDecember26.2004.Theearthquakegeneratedatsunamithatwasamongthedeadliestdisastersinmodernhistory.Atmagnitudeof9.0,itwasthelargestearthquakesice9.2magnitudeGreatAlaskaEarthquakein1964.TheearthquakeoriginatedintheIndianOcean,offthewesterncoastofnorthernSumatra,Indonesia.TheresultingtsunamidevastatedtheshoresofIndonesia,SriLanka,SouthIndia,Thailandandothercountrieswithwavesupto30mhigh.ItcausedseriousdamageanddeathsasfarastheeastcoastofAfrica,withthefurthestrecordeddeathduetothetsunamioccuringatPortElizabethinSouthAfrica,8000kmawayfromtheepicentre.Anywherefrom228000to310000peoplearethoughttohavediedasaresultofthetsunami,andthecountisnotyetcomplete.