Study of anisotropic velocity structure by splitting analysis of Ps converted waves

通过对源自地壳康拉德和莫霍不连续面和日本列岛下洋板块上边界的Ps转换波的剪切波分裂分析，研究了地壳上、下地壳和地幔楔中的s波极化各向异性。剪切波分裂分析采用了波形互相关法和剥离法。结果表明，上地壳各向异性掩盖了下地壳和地幔楔的Ps相极化各向异性。此外，研究发现，在日本中部和四国地区，横波的各向异性在上地壳和下地壳之间存在差异，在东北地区东部沿海地区，地幔楔中Ps波的快速极化方向基本呈N-S方向趋势。

The S-wave polarization anisotropy is investigated in the upper and lower crust and the mantle wedge by shear-wave splitting analysis of Ps converted waves which originate at the Conrad and Moho discontinuities in the crust and at the upper boundary of oceanic plates subducting beneath the Japan Islands. The waveform cross-correlation method and stripping method are employed for the shear-wave splitting analysis. As a result, the upper crustal anisotropy is shown to mask the Ps phase polarization anisotropy in the lower crust and the mantle wedge. In addition, it is found that in Chugoku and Shikoku districts the anisotropic properties of shear wave are different between the upper and lower crust and that in the east coastal region of Tohoku district the fast polarization directions of Ps waves in the mantle wedge show basically N-S direction trend.