华东地区SKS波分裂研究

SKS Wave Splitting in East China

本文搜集整理了华东地区6个区域地震台网的宽频带数字地震台站SKS波记录资料,使用最小切向能量的网络搜索法,得到了华东地区157个台站下方上地幔各向异性参数。测算结果表明,华东地区各向异性快波偏振方向主体为NW—SE向、南部近E—W向,逐渐呈旋转趋势,与绝对板块运动方向一致;其各向异性主要来自于上地幔,地壳与沉积层对各向异性影响较小;研究区内地下浅部与深部物质的运动模式基本一致,壳幔变形存在垂直连贯变形的特征。

SKS wave splitting measurement is a powerful tool to characterize seismic anisotropy.We have made measurements of SKS wave splitting beneath the east China mainland.We use the technique of minimum energy to determine SKS wave splitting parameters at 157 three-component broadband regional digital stations in East China regions.The results indicate that fast-wave polarization direction for anisotropy is basically in the NW-SE direction in east China and nearly E-W direction in the south,which gradually rotates and is the same with the absolute plate movement direction.The anisotropy is mainly caused by the upper mantle and rarely occasioned by the crust and the sediments.In the study area,the substance movement pattern between the shallow and deep is basically the same and the deformation model of the crust and the mantle possibly experiences vertically coherent deformation.