利用GPS和震源机制解研究青藏块体东北部构造应力场方向变化特征
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摘要
利用1970年以来至今青藏块体东北部大量的震源机制解,分时间统计其主压应力方位并求其归一化分布。根据P轴的优势分布方位,推测其主压应力方向。同时,借助有限元方法,利用GPS大地水平形变观测资料,把1999年以来青藏块体东北部大量的GPS资料经过解算,计算其最大主应变率场及最大剪切应变率场。将震源机制解P轴的主压应力方向和GPS计算的最大主应力方向进行对比,分析青藏块体东北部构造应力场随时空的变化特点及时空差异性,探讨震源机制解P轴的优势分布方位、GPS资料的最大主应力方向与地震孕育之间的关系。
Using northeast Qinghai and Xizang block body massive focal mechanism solutions of earthquakes since 1970,it is counted the compression stress position and normalized total direction of tectonic stress by years.According to the P axis superiority distribution position,the compression stress direction is extrapolated.At the same time,with the aid of the finite element method and the GPS earth horizontal deformation observed data,in northeast Qinghai and Xizang block body,the massive GPS material is calculated since 1999 after the solution,and calculated the maximum principal strain rate field and the great shearing strain rate field.To contrast between the compression stress direction of the P axis of focal mechanism solutions of earthquakes and the GPS calculational biggest principal stress direction,it is analyzed the structural stress field in northeast Qinghai and Xizang block with the changes of space and time characteristics and differences.And it is discussed the relations among the focal mechanism solutions of earthquakes,the P axis superiority distribution position,the GPS material biggest principal stress direction and earthquakes.
Using northeast Qinghai and Xizang block body massive focal mechanism solutions of earthquakes since 1970,it is counted the compression stress position and normalized total direction of tectonic stress by years.According to the P axis superiority distribution position,the compression stress direction is extrapolated.At the same time,with the aid of the finite element method and the GPS earth horizontal deformation observed data,in northeast Qinghai and Xizang block body,the massive GPS material is calculated since 1999 after the solution,and calculated the maximum principal strain rate field and the great shearing strain rate field.To contrast between the compression stress direction of the P axis of focal mechanism solutions of earthquakes and the GPS calculational biggest principal stress direction,it is analyzed the structural stress field in northeast Qinghai and Xizang block with the changes of space and time characteristics and differences.And it is discussed the relations among the focal mechanism solutions of earthquakes,the P axis superiority distribution position,the GPS material biggest principal stress direction and earthquakes.
引文
[1]郭良迁,李延兴,黄立人,等.北京地区近十年应变场变化特征[J].大地测量与地球动力学,2006,26(3):46~52.
[2]王双绪,张晓亮,张希,等.昆仑8.1级地震前青藏块体东北缘构造运动特征[J].大地测量与地球动力学,2004,24(1):50~55.
[3]张希,江在森,王琪,等.青藏高原北部地区构造变形特征及与强震关系[J].地球物理学进展,2004,19(2):364~371.
[4]江在森,张希,崔笃信,等.青藏块体东北缘近期地壳水平运动与变形[J].地球物理学报,2001,44(5):636~644(特刊).
[5]陈兵,江在森,王双绪,等.利用非连续变形数值方法研究块体运动及其应力场初探[J].地壳形变与地震,2000,20(1):38~42.
[2]王双绪,张晓亮,张希,等.昆仑8.1级地震前青藏块体东北缘构造运动特征[J].大地测量与地球动力学,2004,24(1):50~55.
[3]张希,江在森,王琪,等.青藏高原北部地区构造变形特征及与强震关系[J].地球物理学进展,2004,19(2):364~371.
[4]江在森,张希,崔笃信,等.青藏块体东北缘近期地壳水平运动与变形[J].地球物理学报,2001,44(5):636~644(特刊).
[5]陈兵,江在森,王双绪,等.利用非连续变形数值方法研究块体运动及其应力场初探[J].地壳形变与地震,2000,20(1):38~42.
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