中国西部现今地壳形变与地震活动特征
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摘要
以1999-2004年间中国西部地区近650个GPS站点的观测资料为基础,采用二维"高张力样条"函数内插算法获得了连续地壳形变场。结果表明,相对于稳定欧亚参考框架,中国西部现今地壳运动西强东弱,北向运动从西向东逐渐减弱,东向运动逐渐增强,青藏高原东缘及附近地区是东向运动的消减区带;主应变从西向东由压缩应变转变为拉伸应变;最大剪应变主要位于喜马拉雅地块及其东部地区;中国西部地区地震活动在空间分布上似乎集中发生在印度板块北东向挤压欧亚板块的两条共扼带内,与地壳形变场有一定对应关系,地壳形变的高应变率区为中强地震多发地带。
Based on the measurements of about 650 GPS stations in Western China observed in the period from 1999 to 2004,it uses the "spline in tension" interpolation method to obtain a continuous velocity field of crustal movement.The results indicate that in a stable Eurasia reference frame,the crustal movement in the western part of the region is larger than that of the eastern part.From West to East,the north component of the movement gradually becomes smaller,and the east component gradually becomes higher.The east edge of the Tibet Plateau and its vicinity are areas with declined east movement.The principal strain is gradually changing from compression in the western area to extension in the eastern area.The high shear strain rates are located in the Himalayan block and its east regions.It seems that many earthquakes happened along two conjugate zones in Chinese mainland produced by the convergence between the India and Eurasia during the period from 1995 to 2006.The seismic activity is corresponding to crustal deformation rate,i.e.more earthquakes occurred in the regions with higher strain rates.
Based on the measurements of about 650 GPS stations in Western China observed in the period from 1999 to 2004,it uses the "spline in tension" interpolation method to obtain a continuous velocity field of crustal movement.The results indicate that in a stable Eurasia reference frame,the crustal movement in the western part of the region is larger than that of the eastern part.From West to East,the north component of the movement gradually becomes smaller,and the east component gradually becomes higher.The east edge of the Tibet Plateau and its vicinity are areas with declined east movement.The principal strain is gradually changing from compression in the western area to extension in the eastern area.The high shear strain rates are located in the Himalayan block and its east regions.It seems that many earthquakes happened along two conjugate zones in Chinese mainland produced by the convergence between the India and Eurasia during the period from 1995 to 2006.The seismic activity is corresponding to crustal deformation rate,i.e.more earthquakes occurred in the regions with higher strain rates.
引文
[1]刘经南,姚宜斌,施闯.中国地壳运动整体速度场模型的建立方法研究[J].武汉大学学报:信息科学版,2002,27(4):331-336.
[2]王琪,张培震,马宗晋.中国大陆现今构造变形GPS观测数据与速度场[J].地学前缘,2002,9(2):415-429.
[3]党亚民,晁定波,许才军,等.利用GPS形变资料确定地壳形变的应变特征[J].测绘科学,2001,26(3):10-13.
[4]杨国华,李延兴,韩月萍,等.中国西部地壳现今变形特征及其机制探讨[J].测绘学报,2002,31(4):292-298.
[5]杨国华,李延兴,韩月萍,等.由GPS观测结果推导中国大陆现今水平应变场[J].地震学报,2002,24(4):337-347.
[6]张希,刘文义,王双绪,等.西北地区近期地壳水平运动与构造变形特征[J].中国地震,2006,22(1):43-54.
[7]王辉,张国民,吴云,等.中国大陆活动地块变形与地震活动的关系[J].中国地震,2003,19(3):243-254.
[8]石耀霖,朱守彪.用GPS位移资料计算应变方法的讨论[J].大地测量与地球动力学,2006,26(1):1-8.
[9]甘卫军,沈正康,张培震,等.青藏高原地壳水平差异运动的GPS观测研究[J].大地测量与地球动力学,2004,24(1):29-35.
[10]Wessel P,Bercovici D.Interpolation with spline in ten-sion:a Green’s Function approach[J].MathematicalGeology,1998,30(1):77-93.
[11]Savage J C,Gan W,Svarc J L.Strain accumulation androtation in the Eastern California Shear Zone[J].J.Geophys.Res.,2001,106(B10):21 995-22 007.
[2]王琪,张培震,马宗晋.中国大陆现今构造变形GPS观测数据与速度场[J].地学前缘,2002,9(2):415-429.
[3]党亚民,晁定波,许才军,等.利用GPS形变资料确定地壳形变的应变特征[J].测绘科学,2001,26(3):10-13.
[4]杨国华,李延兴,韩月萍,等.中国西部地壳现今变形特征及其机制探讨[J].测绘学报,2002,31(4):292-298.
[5]杨国华,李延兴,韩月萍,等.由GPS观测结果推导中国大陆现今水平应变场[J].地震学报,2002,24(4):337-347.
[6]张希,刘文义,王双绪,等.西北地区近期地壳水平运动与构造变形特征[J].中国地震,2006,22(1):43-54.
[7]王辉,张国民,吴云,等.中国大陆活动地块变形与地震活动的关系[J].中国地震,2003,19(3):243-254.
[8]石耀霖,朱守彪.用GPS位移资料计算应变方法的讨论[J].大地测量与地球动力学,2006,26(1):1-8.
[9]甘卫军,沈正康,张培震,等.青藏高原地壳水平差异运动的GPS观测研究[J].大地测量与地球动力学,2004,24(1):29-35.
[10]Wessel P,Bercovici D.Interpolation with spline in ten-sion:a Green’s Function approach[J].MathematicalGeology,1998,30(1):77-93.
[11]Savage J C,Gan W,Svarc J L.Strain accumulation androtation in the Eastern California Shear Zone[J].J.Geophys.Res.,2001,106(B10):21 995-22 007.
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