兰州地区活动构造的基本特征

1,2(1.,257004;2.,730000):NWWNNW2,NWW2,,,112571NNW,,138-634144061419955182,NWWNNW,,:;;;;:P315.2:A:1005-586X(2002)03-0035-060,,,,,11257,138-6344066,,,,,,[13],,,,1:11(1),:2002-06-03:(1965-),,,,14320029EARTHQUAKERESEARCHINPLATEAUVol114No13Sep12002NWWNNW2,,NWW-,(F1)(F2)(F3)(F4)4,,[4,5],,(F5)(F6)1NNW,2,NWWNNW2,(F7)(F8),(F9)(F10)(F11)1;2N-Q;3;4;5;6Q4;7Q3;8;9;10;F1;F2;F3;F4;F5;F6;F7;F8;F9;F10;F111Fig11DistributionofactivetectonicsinLanzhouarea1.11,N60W,115km,4,,,...2002()6314,3173mm/a[4],2,5850500,2060420,3800;2,1682080,108001401,1245560,,11257[5]1.2,,,NW15,100km,2-,NE,19955.8,1440614512,1.3:NWW,35km15km,1,NNW,12km15km,2,,2:(1)4NWW-,,,31NEE,,NE,NWW,-,,,,,,,[6],-,,(2),,733:1,,,,[7],,,138-63414406145121995518-3:,NE-NEE,,2,;2,,NNWNWW,,11257,,56,NEE,,NE2-,-,,56,(2),4,,:(1),,,,(2),15,,,,(3),11257,16295121932583141;2;3;4Q4;5Q3;6;7;82Fig12DynamicpatternofthetectonicdeformationinlateQuaternaryinLanzhouarea,933::[1],.[M].:,199318891.[2],,.1125710[J].,1997,15(1):3744.[3],,,.1995722518[J].,1996,8(3):19.[4],,,.[J].,2002,24(1):199205.[5],,,.11257[J].,2002,18(1):6775.[6],,,.[J].,1999,6(3):121132.[7]SuppeJ,MedwedeffD.A1Geometryandkinematicsoffault-propagationfolding1EcologueGeo11Helv1,1990,83(3):4094541PRINCIPALFEATURESOFTHEACTIVETECTONICSINLANZHOUAREADAIJu2chang1,YUANDao2yang2(11ShengliOilFieldWorkersCollegeinShandongProvince,Dongying257004,China;21LanzhouInstituteofSeismology,CSB,Lanzhou730000,China)Abstract:Lanzhouareadevelopedtwogroupsofdominantactivetectonics:onegroupisNWWdirec2tion,anotheroneisNNWdirection1BytheboundaryofHekou,thestructurepatternofeasternareaisNWWdirectionMaxianshan-Xinglongshanreverseleftlateralstrike-slipfaultsystem1Theirnewactivitiesareverystrong,sotheyformedthemaincontrolledearthquakefaults,Lanzhouearthquakewithmagnitude7in1125hadjusthappenedinthewestsegmentofthisfaultzone1InthewesternareaofHekou,therearegroupofarcthrust-foldzonesbyNNWdirection,suchasthenorthernmarginfaultofLajishanMountainandZhuanglanghefault,etc1Thecharacteristicofdeformationisfaultpropagationfolding,theirnewactivitieshadcausedaseriesofearthquakeshappening,suchasJincheng-LongxiMs634earthquakein138,YongdengMs614earthquakeandKushuiMs512earthquakein1440,YongdengMs518earthquakein1995,etc1Lanzhoubasinisblendedinthetwogroupsofactivetectonics,therearealsodevelopedtwogroupsofNWWandNNWdirectionsec2ondaryfaultswhichrelativeeachother,suchastheLiujabufault,Jinchengguanfault,LeitanhefaultandShengouqiaofault,etc1Thesefaultshavethestructuralconditiontobreedandhappenmiddleandstrongearthquakes1Keywords:Lanzhouarea;Activetectonic;Historicalearthquake;Arcstructure;Fault-propagationfold0414