巴颜喀拉块体北东地区现今水平运动与变形
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摘要
本文利用GPS数据研究了巴颜喀拉块体北东地区现今水平运动与变形特征。在球坐标系中解算了各应变分量,分析了应变率场的空间分布特征,并与地球物理学和地震地质学研究结果进行了综合对比分析。最新的GPS速度场结果表明,巴颜喀拉块体北东地区与高原整体运动性质一样具有顺时针向南东方向旋转的特征,自西向东和北东方向测站水平运动速度呈现明显的衰减特征。应变场结果显示,研究区以北东向的主压应变为主,伴随着近北西向的张性应变。应变较强的区域主要分布在活动块体的边界断裂——东昆仑断裂带的东段塔藏段和龙门山断裂带上。东昆仑断裂带东段塔藏段的主压应变明显,结合地震地质和活动构造资料,认为东昆仑断裂带东段塔藏段的运动性质自西向东发生了改变,水平滑动速率逐渐减小,垂向运动逐渐增强。研究区GPS速度场和应变场的这一变形特征表明,青藏高原内部的块体运动特征较为明显,变形主要集中在作为活动块体边界的活动断裂带上,边界断裂带的运动特征在调节活动块体间的相互运动中起着重要作用。
We have collected GPS data in the period of 2001—2009 from the Crustal Motion Observation Network of China in northwest of Sichuan,and the newest observation data from observed campaign stations which were built under the support of the National Key Basic Research Development Program,to study the characteristics of present-day crustal horizontal motion velocities in the research zone.Strain rate components are computed in spheric coordinate system.Analyses of the spatial distribution strain rate fileds derived from GPS measurements are carried out in contrast with seismological and geological results.Results show that the horizontal motion of the GPS stations are consistent with the clockwise rotation of the whole Tibetan Pleatau around the Eastern Himalayan syntaxis.From west to east and northeast,the velocity decreases obviously.The principal compression strain rates are apparently greater than principal extension strain rates,especially in Tazang fault,the eastern part of Dongkunlun fault and the middle part of the Longmenshan fault.The principal compress strain is obviously in the eastern segment of the Dongkunlun fault.Combining analysises with the data of earthquake geology and active tectonics,we suggest that the motion characteristics may be changed from west to east,in the west,the fault shows an obviously left lateral strike-slip,but in the eastern segment,it not only show a left lateral motion but also an compress movement.The motion characteristics of the boundary fault plays an important part in adjusting the relative motion with the blocks.Based on the velocity filed and strain filed from GPS data,we think that the motion in the reasearch zone can be thought as a block motion,most obvious deformation mainly on the boundary faults of the active blocks.
We have collected GPS data in the period of 2001—2009 from the Crustal Motion Observation Network of China in northwest of Sichuan,and the newest observation data from observed campaign stations which were built under the support of the National Key Basic Research Development Program,to study the characteristics of present-day crustal horizontal motion velocities in the research zone.Strain rate components are computed in spheric coordinate system.Analyses of the spatial distribution strain rate fileds derived from GPS measurements are carried out in contrast with seismological and geological results.Results show that the horizontal motion of the GPS stations are consistent with the clockwise rotation of the whole Tibetan Pleatau around the Eastern Himalayan syntaxis.From west to east and northeast,the velocity decreases obviously.The principal compression strain rates are apparently greater than principal extension strain rates,especially in Tazang fault,the eastern part of Dongkunlun fault and the middle part of the Longmenshan fault.The principal compress strain is obviously in the eastern segment of the Dongkunlun fault.Combining analysises with the data of earthquake geology and active tectonics,we suggest that the motion characteristics may be changed from west to east,in the west,the fault shows an obviously left lateral strike-slip,but in the eastern segment,it not only show a left lateral motion but also an compress movement.The motion characteristics of the boundary fault plays an important part in adjusting the relative motion with the blocks.Based on the velocity filed and strain filed from GPS data,we think that the motion in the reasearch zone can be thought as a block motion,most obvious deformation mainly on the boundary faults of the active blocks.
引文
[1]张培震.青藏高原东缘川西地区的现今构造变形、应变分配与深部动力过程[J].中国科学D辑:地球科学,2008,38(9):1041-1056.
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[6]江在森,马宗晋,张希,等.青藏块体东北缘水平应变场构造变形分析[J].地震地质,2001,23(3):337-345.
[7]王琪,张培震,牛之俊,等.中国大陆现今地壳运动和构造变形[J].中国科学D:地球科学,2001,31(1):530-536.
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[10]张培震,沈正康,王敏,等.青藏高原及周边现今构造变形的运动学[J].地震地质,2004,26(3):367-377.
[11]孟国杰,申旭辉,Vladimir Smirnov,等.堪察加地区现今地壳运动与变形特征研究[J].地球物理学报,2009,52(3):720-731.
[12]武艳强,江在森,杨国华,等.利用多面函数整体求解GPS应变场的方法及应用[J].武汉大学学报.信息科学版,2009,34(9):1085-1089.
[13]孟国杰,申旭辉,伍吉仓,等.GPS地壳形变监测网应变解算方法与程序设计[J].大地测量与地球动力学,2006,26(2):70-74.
[14]伍吉仓,邓康伟,陈永奇.三角形形状因子对地壳形变计算精度的影响[J].大地测量与地球动力学,2003,23(3):27-30.
[15]Tom Parsons,Chen Ji,Eric Kirby.Stress changes from the 2008 Wenchuan earthquake and in-creased hazard in the Sichuan basin[J].Nature letters,2008,Vol 454,doi:10.1038.
[16]Xiong X,Shan B,Zheng Y,et al.Stress transfer and its implications for earthquake hazard on theKunlun Fault,Tibet[J].Tectonophysics,2010,482:216-225.
[17]Wen X Z,Yi G X,Xu X W.Background and precursory seismicities along and surrounding the Kun-lun fault before the MS8.1,2001,Kokoxili earthquake,China[J].Journal of Asian Earth Sciences,2007,30:63-72.
[18]江在森,马宗晋,张希,等.GPS初步结果揭示的中国大陆水平应变场与构造变形[J].地球物理学报,2003,46(3):352-358.
[19]谢富仁,崔效锋,赵建涛,等.中国大陆及邻区现代构造应力场分区[J].地球物理学报,2004,47(4):654-662.
[20]崔效锋,谢富仁,赵建涛.中国及邻区震源机制解分析及其在构造应力场研究中的应用[M].北京:地质出版社,2001.49-58.
[21]马杏垣.中国岩石圈动力学图集[M].北京:中国地图出版社,1989.2-68.
[22]崔效锋,谢富仁.利用震源机制解对中国西南及邻区进行应力分区的初步研究[J].地震学报,1999,21(5):513-522.
[23]李延兴,李智,张静华,等.中国大陆及周边地区的水平应变场[J].地球物理学报,2004,47(2):222-231.
[24]Tapponnier P,Molnar P.Active faulting and Cenozoic tectonics of China[J].J Geophys Res,1982,82:2 905-2 930.
[25]Tapponnier P,Peltzer G,Le Dain A Y,et al.Propagating extrusion tectonics in Asia;new insightsfrom simple experiments with plasticine[J].Geology,1982,10:611-616.
[26]Peltzer G,Tapponnier P.Formation and evolution of strike-slip faults,rifts,and basin during India-Asia collision:An experiment approach[J].J Geophys Res,1988,93:15 085-15 117.
[27]Avouac J P,Tapponnier P.Kinematic model of active deformation in central Asia[J].Geophys ResLett,1993,20:895-898.
[28]England P C,Mckenzie D.A thin viscous sheet model for continental deformation[J].Geophys JInt,1982,70(2):295-321.
[29]England P C,Houseman G A.Finite strain calculations of continental deformation2:Comparisonwith the India-Asia collision[J].J Geophys Res,1986,91:3 664-3 667.
[30]Vilotte J P,Madariaga R,Daignieres M,et al.Numerical study of continent collision influences ofbuoyancy forces and an initial stiff inclusion[J].G eophys J Int,1986,84:279-310.
[31]李陈侠.东昆仑断裂带东段(玛沁—玛曲)晚第四纪长期滑动习性研究[D].北京:中国地震局地质研究所,2009.
[32]胡朝忠.塔藏断裂晚第四纪活动性研究[D].北京:中国地震局地震预测研究所,2010.
[33]Wessel P,Smith W H F.A global,self-confident,hierarchical,high-resolution shoreline database[J].J Geophys Res,1996,101:8 741-8 743.
[2]中国地震局震害防御司(编).中国近代地震目录[M].北京:中国科学技术出版社,1999.1-637.
[3]http://www.csi.ac.cn/sichuan.(中国地震台网中心.2008.)
[4]Chen Z L,B.C.Burchfiel,Liu Y,et al.Global Positioning System measurements from eastern Ti-bet and their implications for India/Eurasia intercontinental deformation[J].J Geophys Res,2000,105(7):16 215-16 227.
[5]江在森,张希,崔笃信,等.青藏块体东北缘近期水平运动与变形[J].地球物理学报,2001,44(5):636-644.
[6]江在森,马宗晋,张希,等.青藏块体东北缘水平应变场构造变形分析[J].地震地质,2001,23(3):337-345.
[7]王琪,张培震,牛之俊,等.中国大陆现今地壳运动和构造变形[J].中国科学D:地球科学,2001,31(1):530-536.
[8]Shen Z K,LüJ N,Wang M,et al.Contemporary crustal deformation around the southeast border-land of theTibetan Plateau[J].J Geophys Res,2005,110,B11409,doi:10.1029/2004JB003421.
[9]Gan W,Zhang P Z,Shen Z K,et al.Present-day crustal motion within the Tibetan Plateau inferredfrom GPS measurements[J].J Geophys Res,2007,112,B08416,doi:10.1029/2005JB004120.
[10]张培震,沈正康,王敏,等.青藏高原及周边现今构造变形的运动学[J].地震地质,2004,26(3):367-377.
[11]孟国杰,申旭辉,Vladimir Smirnov,等.堪察加地区现今地壳运动与变形特征研究[J].地球物理学报,2009,52(3):720-731.
[12]武艳强,江在森,杨国华,等.利用多面函数整体求解GPS应变场的方法及应用[J].武汉大学学报.信息科学版,2009,34(9):1085-1089.
[13]孟国杰,申旭辉,伍吉仓,等.GPS地壳形变监测网应变解算方法与程序设计[J].大地测量与地球动力学,2006,26(2):70-74.
[14]伍吉仓,邓康伟,陈永奇.三角形形状因子对地壳形变计算精度的影响[J].大地测量与地球动力学,2003,23(3):27-30.
[15]Tom Parsons,Chen Ji,Eric Kirby.Stress changes from the 2008 Wenchuan earthquake and in-creased hazard in the Sichuan basin[J].Nature letters,2008,Vol 454,doi:10.1038.
[16]Xiong X,Shan B,Zheng Y,et al.Stress transfer and its implications for earthquake hazard on theKunlun Fault,Tibet[J].Tectonophysics,2010,482:216-225.
[17]Wen X Z,Yi G X,Xu X W.Background and precursory seismicities along and surrounding the Kun-lun fault before the MS8.1,2001,Kokoxili earthquake,China[J].Journal of Asian Earth Sciences,2007,30:63-72.
[18]江在森,马宗晋,张希,等.GPS初步结果揭示的中国大陆水平应变场与构造变形[J].地球物理学报,2003,46(3):352-358.
[19]谢富仁,崔效锋,赵建涛,等.中国大陆及邻区现代构造应力场分区[J].地球物理学报,2004,47(4):654-662.
[20]崔效锋,谢富仁,赵建涛.中国及邻区震源机制解分析及其在构造应力场研究中的应用[M].北京:地质出版社,2001.49-58.
[21]马杏垣.中国岩石圈动力学图集[M].北京:中国地图出版社,1989.2-68.
[22]崔效锋,谢富仁.利用震源机制解对中国西南及邻区进行应力分区的初步研究[J].地震学报,1999,21(5):513-522.
[23]李延兴,李智,张静华,等.中国大陆及周边地区的水平应变场[J].地球物理学报,2004,47(2):222-231.
[24]Tapponnier P,Molnar P.Active faulting and Cenozoic tectonics of China[J].J Geophys Res,1982,82:2 905-2 930.
[25]Tapponnier P,Peltzer G,Le Dain A Y,et al.Propagating extrusion tectonics in Asia;new insightsfrom simple experiments with plasticine[J].Geology,1982,10:611-616.
[26]Peltzer G,Tapponnier P.Formation and evolution of strike-slip faults,rifts,and basin during India-Asia collision:An experiment approach[J].J Geophys Res,1988,93:15 085-15 117.
[27]Avouac J P,Tapponnier P.Kinematic model of active deformation in central Asia[J].Geophys ResLett,1993,20:895-898.
[28]England P C,Mckenzie D.A thin viscous sheet model for continental deformation[J].Geophys JInt,1982,70(2):295-321.
[29]England P C,Houseman G A.Finite strain calculations of continental deformation2:Comparisonwith the India-Asia collision[J].J Geophys Res,1986,91:3 664-3 667.
[30]Vilotte J P,Madariaga R,Daignieres M,et al.Numerical study of continent collision influences ofbuoyancy forces and an initial stiff inclusion[J].G eophys J Int,1986,84:279-310.
[31]李陈侠.东昆仑断裂带东段(玛沁—玛曲)晚第四纪长期滑动习性研究[D].北京:中国地震局地质研究所,2009.
[32]胡朝忠.塔藏断裂晚第四纪活动性研究[D].北京:中国地震局地震预测研究所,2010.
[33]Wessel P,Smith W H F.A global,self-confident,hierarchical,high-resolution shoreline database[J].J Geophys Res,1996,101:8 741-8 743.
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