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1、WarmUp12/4Whendoesliquefactionoccur?WhenlooselyconsolidatedsoilssaturatedwithwaterareshakenbyearthquakewavesWhatfactorsdeterminehowmuchdamageisinflictedonabuilding?Intensityanddurationofvibrations,natureofmaterialonwhichthestructureisbuilt,anddesignofthestructureWhy
2、isitincorrecttorefertotsunamisastidalwaves?Tidalwavesarecausedbythegravitationalpullofthesunandmoon,whiletsunamisarecausedbyearthquakesGoBruins!Earth’sLayeredStructureLayersDefinedbyCompositionIfEarthweremadeupofthesamematerialsthroughoutitsinterior,seismicwaveswoul
3、dtravelinstraightlinesatconstantspeedsSeismicwavesreachingseismographslocatedfartherfromanearthquaketravelatfasteraveragespeeds,duetoincreasedpressureatdepthEarth’sinteriorconsistsofthreemajorzonesdefinedbyitschemicalcomposition–thecrust,mantle,andcorePathsofSeismic
4、RaysTheCrustCrust–thin,rocky,outerlayerofEarth;dividedintooceanicandcontinentalcrustTheoceaniccrustisroughly7kilometersthickandcomposedoftheigneousrocksbasaltandgabbroThecontinentalcrustis8-75kilometersthick(avg.40km)andconsistsmostlyofthegraniticrockgranodioriteThe
5、rocksoftheoceaniccrustareyoungerthentherocksofthecontinentalcrustMantleandCoreMantle–asolid,rockyshellthatextendstoadepthof2890kmOver82%ofEarth’smassiscontainedinthemantleTheboundarybetweenthecrustandmantlerepresentsachemicalcompositionchangeCore–aspherecomposedofan
6、iron-nickelalloyLayersDefinedbyPhysicalPropertiesEarth’sinteriorhasagradualincreaseintemperature,pressure,anddensitywithdepthDependingonthephysicalenvironment(temperatureandpressure),amaterialmaybehavelikeabrittlesolid,aputty,oraliquidEarthcanbedividedintolayersbase
7、donphysicalproperties–thelithosphere,asthenosphere,outercore,andinnercore.LithosphereandAsthenosphereLithosphere–relativelycool,rigidshellconsistingofthecrustanduppermostmantleAveragesabout100kilometersinthicknessAsthenosphere–soft,comparativelyweaklayerbeneaththeli
8、thosphereTherockswithintheasthenospherearecloseenoughtotheirmeltingpointsthattheyareeasilydeformedLowerMantleFromadepthof660kmdowntonearth
