中国大陆地壳上地幔S波品质因子三维层析成像

根据欧亚大陆及西太平洋地区58个数字地震台站2861个长周期波形记录，从中挑选出符合条件的223对经过中国大陆的双台路径记录，采用相匹配滤波和频率域维纳滤波相结合的方法，计算出双台之间的混合路径衰减系数. 对中国大陆区域进行网格划分，通过网格化反演得到中国大陆区域每个网格单元的纯路径衰减系数. 根据速度和密度模型，对每个网格单元进行深度反演，得到10～350km的S波品质因子Qβ，进而得到整个中国大陆的S波品质因子分布. 结果显示：研究区域的Qβ横向和纵向变化非常显著，能够明显区分软流圈结构，各个大构造单元的Qβ结构呈现出显著的变化. 这为解释中国大陆区域地球内部介质性质和探讨地球动力学提供了丰富的信息.

TOMOGRAPHY OF THE 3-D S-WAVE QUALITY FACTOR OF THE CRUST AND UPPER MANTLE IN CHINA

We selected 223 pairs of Rayleigh wave from 2681 waveforms recorded by 58 tations in the Euro Asia land and west pacific region. The fundamental mode surface wave was separated using the phase match for each seismograms. The fundamental mode interstation attenuation coefficients γ was calculated using the two station methods. In order to avoiding the negative attenuation coefficients, the frequence domain Wiener filter was used. We inverse the attenuation coefficient of the Rayleigh wave in China area with grids 4°×4°, calculate the layer Qβ in each grid, and then get the distribution of Qβ with different depth in China area. This paper mainly inverses the S wave factor using the surface wave attenuation characters. The result shows that the lateral and vertical variations of Qβ are very clear in the whole area and the asthenosphere, and some big structure area is also shown very clearly. This study provides plentiful information for the interpretation of the material property and geodynamic of the earth interior in China area, and also help to understand the interior visci dity structure in China area.