Offshore Fault Geometrics in the Pearl River Estuary, Southeastern China： Evidence from Seismic Reflection Data

ThePearlRiverEstuary（PRE）islocatedattheonshore-offshoretransitionzonebetweenSouthChinaandSouthChinaSeaBasin,anditisofgreatsignificantvalueindiscussingtectonicrelationshipsbetweenSouthChinablockandSouthChinaSeablockandseismicactivitiesalongtheoffshoreactivefaultsinPRE.However,theresearchesongeometriccharacteristicsofoffshorefaultsinthisareaareextremelylacking.ToinvestigatetheoffshorefaultdistributionandtheirgeometricfeaturesinthePREingreaterdetail,weacquiredthirteenseismicreflectionprofilesin2015.Combiningtheanalysisoftheseismicreflectionandfree-airgravityanomalydata,thispaperrevealedthelocation,continuity,andgeometryofthelittoralfaultzoneandotheroffshorefaultsinPRE.ThelittoralfaultzoneiscomposedofthemajorDanganIslandsfaultandseveralparallel,high-angle,normalfaults,whichmainlytrendnortheasttonortheast-to-eastanddiptothesoutheastwithlargedisplacements.Thefaultzoneisdividedintothreedifferentsegmentsbythenorthwest-trendingfaults.Moreover,thebasementdeptharoundDanganIslandsisveryshallow,whileitsuddenlyincreasesalongtheislandswestwardandsouthward.Thesehasresultedintheislandsandneighboringareasbecomingtheplaceswherethestressaccumulateseasily.Theseismogenicpatternofthisareaiscloselyrelatedtothecomprehensiveeffectofintersectingfaultstogetherwiththelowvelocitylayer.