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43个三分量台站地震记录的各向异性计算结果显示:印度河—雅鲁藏布江缝合带两侧的各向异性特征明显不同,其北面较古老的班公湖—怒江缝合线和金沙江缝合线没有明显反映。各向异性方向与地表构造线方向多存在着明显的差异,因此不能简单地用与造山带走向相一致的上地幔变形来解释。另一方面各向异性在空间上的变化规律,如沿雅鲁藏布江两侧相互垂直的各向异性方向;羌塘地区较强的各向异性与Sn(一种沿莫霍面传播的折射横波)缺失区存在良好的对应关系。这些说明青藏高原还存在更复杂的碰撞变形机制。就现有资料我们认为,青藏高原的抬升是由于Argand式俯冲和Dewey式的均匀缩短联合作用的结果。
The anisotropy of the 43 three-component station seismograms shows that the anisotropy of the two sides of the Indus-Brahmaputra suture zone is significantly different from that of the northern Bangang-Nujiang suture and the Jinshajiang suture Clearly reflected. The direction of anisotropy is different from the direction of the surface structure line. Therefore, it can not be simply explained by the deformation of the upper mantle consistent with the orogenic direction. On the other hand, anisotropy changes spatially in the direction of anisotropy perpendicular to each other along both sides of the Brahmaputra. The strong anisotropy in the Qiangtang region and the absence of the Sn (a refracted transverse wave propagating along the Moho) There is a good correspondence between districts. All these show that there are still more complicated collision deformation mechanisms in the Qinghai-Tibet Plateau. Based on the available data, we think that the uplift of the Tibetan Plateau is the result of the combined effect of Argand-type subduction and Dewey-type uniform shortening.