P-waveandS-wavereceiverfunctionanalyseshavebeenperformedalongaprofileconsistedof27broadbandseismicstationstoimagethecrustalanduppermantlediscontinuitiesacrossNortheastChina.TheresultsshowthattheaverageMohodepthvariesfromabout37kmbeneaththeDaxing’anlingorogenicbeltinthewesttoabout33kmbeneaththeSongliaoBasin,andtoabout35kmbeneaththeChangbaimountainregionintheeast.OurresultsrevealthattheMohoisgenerallyflatbeneaththeDaxing’anlingregionandaremarkableMohooffset(about4km)existsbeneaththebasin-mountainboundary,theDaxing’anling-TaihangGravityLine.BeneaththeTanlufaultszone,whichseperatestheSongliaoBasinandChangbairegion,theMohoisupliftandthecrustalthicknesschangesrapidly.WeinterpretthisfeatureasthattheTanlufaultsmightdeeplypenetrateintotheuppermantle,andfacilitatethemantleupwellingalongthefaultsduringtheCenozoicera.Theaveragedepthofthelithosphereasthenosphereboundary(LAB)is*80kmalongtheprofilewhichisthinnerthananaveragethicknessofacontinentallithosphere.TheLABshowsanarc-likeshapeinthebasin,withtheshallowestpartapproximatelybeneaththecenterofthebasin.TheupliftLABbeneaththebasinmightberelatedtotheextensivelithosphericstretchingintheMesozoic.Inthemantletransitionzone,astructurallycomplicated660kmdiscontinuitywithamaximum35kmdepressionbeneaththeChangbairegionisobserved.The35kmdepressionisroughlycoincidentwiththelocationofthestagnantwesternpacificslabontopofthe660kmdiscontinuityrevealedbytherecentPwavetomography.
