中国大陆及海域Love波层析成像

收集了研究区域(68°-150°E,5°-55°N)内33个数字地震台站记录的面波资料,利用多重滤波技术提取了4000余条路径上的Love波群速度频散曲线. 将研究区域划分成1°×1°网格,采取Occam反演方法得到了7.3-184s共43个周期的Love波群速度分布图;然后对网格结点进行S波速度结构反演,得出研究区域内420km深度内的地壳上地幔三维速度结构. 并采用Checkerboard方法对分辨率进行检验,得到横向的分辨率约为3°-5°. 研究结果表明:中国大陆地壳上地幔结构的横向不均匀性非常明显,内部结构与地表特征的相关性可以达到0-150km深度. 大陆地区东西分带、南北分块,块体的边界反映比较清晰.

LOVE WAVE SEISMIC TOMOGRAPHY OF CHINA AND VICINAL SEA AREAS

We assembled the surface wave data recorded by 33 digital seismic stations in China and vicinal areas, and extracted group velocity dispersion curves of fundamental-mode Love wave along approximately 4000 paths by means of multiple-filter techniques. The study area was divided into a grid of 1°×1°, and 43 group velocity distribution maps were obtained between 7.3sec and 184sec by means of Occam inversion, afterwards the shear wave velocity structures were inverted for each node. The lateral resolution is about 3°-5° which is tested with checkerboard method. The results show that: the difference of the crust and upper mantle structure in the study area is very significant, the correlation of the interior structure and surface character is down to 100-150km. China continent can be divided into several different blocks, and the block boundary is comparatively clear.