ThePearlRiverEstuaryarea,locatedinthemiddlepartofthesouthernChinacoastalseismicbelt,haslongbeenconsideredapotentialsourceofstrongearthquakesabovemagnitude7.0.Toscientificallyassessthepotentialstrongearthquakeriskinthisarea,athree-dimensionalartificialseismicsoundingexperiment,consistingofareceivingarrayandseabedseismograph,wasperformedtorevealthedeepcrustalstructureinthisregion.Weusedartificialship-borneair-gunexcitationshotsassources,andfixedandmobilestationsasreceiverstorecordseismicdatafromMaytoAugust2015.ThispaperpresentsresultsalongalinefromthewesternsideofthePearlRiverEstuarytothewesternsideoftheBaijing-Gaoming-Jinwanprofile.Atwo-dimensionalvelocitystructurewasconstructedusingseismictravel-timetomography.TheinversionresultsshowthattheMohodepthis27kminthecoastalareaand30kminthenorthwestofthePearlRiverEstuaryarea,indicatingthatthecrustthinsfromlandtosea.Twostructuraldiscontinuitiesandmultiplelow-velocityanomaliesappearinthecrustalsection.Insidebothdiscontinuityzones,alow-velocitylayer,withaminimumvelocityof6.05kms?1,existsatadepthofabout15km,andanother,withaminimumvelocityof6.37kms?1,existsatadepthofabout21.5kmbetweenthemiddleandlowercrust.Theselowvelocitiessuggestthatthediscontinuitiesmayconsistofpartlymoltenmaterial.Earthquakeswithmagnitudeshigherthan5.0occurredinthelow-velocitylayeralongtheprofile.ThedeepKaiping-Enpingfault,rootedinthecrust,maybeoneofthemostimportantchannelsfordeepmaterialupwellingandisrelatedtotectonicmovementsincetheCretaceousinthePearlRiverDeltatectonicriftbasin.
