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Research on Methods Constraining Shear-Wave Splitting and Geodynamical Implication of Shear-Wave Splitting in China

WANG Rui1, MA Zhitu1, Li Fei1,2, Zhou Shiyong1   

  1. 1. Department of Geophysics, Peking University, Beijing 100871; 2. Earthquake Monitor Center of Seismological Bureau of Yunnan Province, Kunming 650224;
  • Received:2009-09-21 Online:2010-11-20 Published:2010-11-20



  1. 1. 北京大学地球物理系, 北京 100871; 2. 云南省地震局地震监测中心, 昆明 650224;

Abstract: Shear-wave splitting is the most simple and direct seismic method to understand the anisotropic property of the earth. The result has important meaning in geodynamics and valuable in the research of earthquake prediction. The authors use the methods proposed by SC1991 and WS1998 to constrain the splitting parameters by analyzing SKS and SKKSphases. The records from 2001 to 2005 are provided by Chinese Seismology Network Center (CENC). Great discrepancies are observed. The splitting time in South-West, South, and North-West part of China is shorter than Middle and Middle-West part of China. Similar patterns between fast direction and GPS velocity direction show coupling effect between lithosphere and asthenosphere. Fast directions are also parallel to plate boundaries in convergent regions and identical to the strike of transcurrent fault. This may imply the coherent deformation between crust and mantle. The length of time window, the possibility of ray-splitting and the dependence of fast direction to back-azimuth are also discussed.

Key words: anisotropy, shear-wave splitting, fast direction, SKS

摘要: 利用中国国家台网2001?2005年的数据, 采用 SC1991 和 WS1998 的方法, 通过分析SKS和SKKS震相, 获得了中国大陆地区国家地震基准观测台的分裂参数。各台站的结果差异较大。西南部、南部、西北部分裂时间比华北及中西部的分裂时间要少。快方向与 GPS 速度场的一致性表明岩石圈与软流圈的耦合现象。快方向在板块会聚带平行于板块边界, 在走滑断层处平行于断层走向。这些都可能表明地壳与地幔的一致变形。讨论了时间窗的截取长度、射线分裂的可能性和快方向随后方位角的变化。

关键词: 各向异性, 横波分裂, 快波方向, SKS

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