We deployed a linear seismic array consisting of 50 broadband stations in the southern part of the Great Xing'an orogenic belt to investigate seismic anisotropy in the Songliao Basin, the orogenic belt and the Erlian Basin by making SKS wave splitting measurements. Different features of anisotropy are revealed on the two sides of the north-south gravity lineament. The anisotropy on the east side of the gravity lineament primarily results from mantle flows in the big mantle wedge above the flat Pacific slab in the mantle transition zone, and the SKS fast polarization direction is generally NW-SE, being consistent with the subduction direction of the western Pacific plate. On the west side of the gravity lineament, the SKS splitting is attributed to freezing anisotropy in the stable lithosphere under the Erlian Basin. The SKS splitting delay times show some changes with azimuths of the teleseismic events, but the fast polarization directions are generally the same, indicating that the anisotropies below these seismic stations have the same origin in the continental lithosphere and active flows in the big mantle wedge.

中文翻译：

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大兴安岭造山带南部剪切波分裂与地幔动力学


我们在大兴安岭造山带南部部署了由50个宽带台站组成的线性地震台阵，通过SKS波分裂测量研究了松辽盆地、造山带和二连盆地的地震各向异性。南北重力线两侧呈现出不同的各向异性特征。重力线东侧的各向异性主要是地幔过渡带平坦太平洋板片上方大地幔楔内的地幔流动造成的，SKS快极化方向总体为NW-SE，与俯冲方向一致。西太平洋板块。在重力线西侧，SKS分裂归因于二连盆地稳定岩石圈的冻结各向异性。 SKS分裂延迟时间随着远震事件的方位角出现一定的变化，但快极化方向基本相同，表明这些地震台下方的各向异性在大陆岩石圈和大地幔楔中的活动流中具有相同的根源。