山西地区地壳剪切波分裂特征

Characteristics of shear-wave splitting in the crust in Shanxi region

  • 摘要: 通过对山西数字地震台网2000年6月—2012年12月的波形记录资料的分析, 使用剪切波分裂系统分析方法, 即SAM综合分析方法, 获得了山西地区18个数字地震台站的快剪切波偏振结果. 结果表明: 位于活动断裂上的台站的快剪切波偏振优势方向与活动断裂的走向基本一致; 个别距离断裂较远的台站的快剪切波偏振优势方向与震源机制解及GPS主压应变方向完全一致; 少数位于几条断裂交汇处的台站的快剪切波偏振优势方向则较为复杂, 与活动断裂的走向和GPS主压应变方向均不一致, 反映了该地区断裂背景和应力分布特征的复杂性.

     

    Abstract: Based on the analysis of seismic waveform data recorded by the Shanxi Digital Seismic Network from June 2000 to December 2012, the dominant polarization directions of fast shear-waves at 18 stations are obtained by use of the systematic analysis method (SAM) of shear-wave splitting in this study. The results show that for the stations located on active faults, the dominant polarization directions of fast shear-waves are mainly consistent with the strike of active faults; for individual stations further away from active faults, the dominant polarization directions are completely consistent with focal mechanism solutions and directions of regional principal compressive strains inferred from GPS data. While for a few stations located at the junction of several faults, the polarization of fast shear-wave is inconsistent with both the strike of active faults and the direction of principal compressive strain from GPS, indicating that faulting background and distribution characteristics of regional stress field are complex in Shanxi region.

     

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