地壳剪切波分裂研究及地震定位误差对剪切波分裂分析的影响

Crustal Share-wave Splitting Research and the Effects of Earthquake Location Error on the Analyzing Results

地壳介质的各向异性主要是由大量充满液体的微裂隙的定向排列引起的,剪切波穿过这种含有微裂隙的介质时会产生分裂。剪切波分裂参数与地壳介质的物理性质有关,与区域应力场有关。在地壳剪切波分裂研究中,地震的定位误差对剪切波分裂参数有影响。本文简单介绍了几种影响定位精度的因素;并对定位误差特别是深度方向的误差所引起的时间延迟变化进行了讨论,比较了不同大小的深度误差对归一化后的时间延迟的影响,定量分析结果显示,深度定位误差对慢剪切波时间延迟影响很大。剪切波分裂分析方法有多种,本文还对不同的剪切波分裂分析方法做了简介。

Seismic anisotropy of the crust is mainly caused by the stress-aligned fluid-saturated grain-boundary cracks. When shear-wave travels through anisotropic media, it will split. The parameter of shear-wave splitting is relative to the physical property of the crust medium and the regional stress field. Earthquake location error has an impact on sharewave splitting parameter, We discuss factors that influence on the accurate location and analyses the variety of the time delay caused by depth location error. We compared the influences of different depth errors on normalized time delays. The result of quantitative analysis shows that depth error can cause a great influence on slow shear-wave time delay. We also introduce and compare some analysis methods of shear-wave splitting.