SUMMARY The northeastern Indian region is characterized by complex lithospheric structure that developed due to collision between the Indian and Eurasian tectonic plates, in the north, and to subduction beneath the Burmese arc, in the east. We report results from joint modelling of Ps and Sp receiver functions and Rayleigh wave group velocity dispersion curves in which a broad search for acceptable models is performed via simulated annealing. We identify three tectonic domains, the Shillong plateau, Brahmaputra valley and Indo-Burma convergence zone (IBCZ), sampled by teleseismic earthquake data recorded by nine broad-band seismic stations. Our results reveal that the region's thinnest crust lies beneath the Shillong plateau, where it increases slightly from the plateau's eastern edge to its centre and reaches a maximum at the western edge of the plateau. Crustal Vp/Vs ratios range between 1.69 and 1.75 for the Shillong plateau, which is consistent with a felsic composition. Deeper Moho depths beneath the Brahmaputra valley, adjacent to the northern front of the Shillong plateau, may be due to the flexure of Indian lithosphere subducting beneath Asia. Low velocity zones are indicated at ∼5–10 km depth beneath the Brahmaputra valley, which may have been developed by NE–SW trending compressional stresses from the collision at the Himalayan arc and subduction at the Burmese arc. The crust is thickest in Kohima, beneath the Naga thrust in the IBCZ, where a high velocity zone is observed for both Vp and Vs at a depth of 25–40 km. This anomaly may be associated with a high velocity slab, trending N–NE to S–SW, that comprises the subducting Indian lithosphere in the IBCZ.

中文翻译：

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通过联合拟合接收器函数和表面波频散绘制西隆高原（印度）和毗邻地区下方的岩石圈地震结构

总结 印度东北部地区的特征是复杂的岩石圈结构，该结构是由于北部印度和欧亚构造板块之间的碰撞以及东部缅甸弧之下的俯冲而形成的。我们报告了 Ps 和 Sp 接收器函数和瑞利波群速度色散曲线的联合建模结果，其中通过模拟退火对可接受的模型进行了广泛的搜索。我们确定了三个构造域，西隆高原、布拉马普特拉河谷和印缅会聚带 (IBCZ)，由九个宽带地震台站记录的远震地震数据采样。我们的研究结果表明，该地区最薄的地壳位于西隆高原下方，从高原略微增加。s 东部边缘到其中心，在高原的西部边缘达到最大值。西隆高原的地壳 Vp/Vs 比率在 1.69 和 1.75 之间，这与长英质成分一致。布拉马普特拉河谷下方更深的莫霍面深度，毗邻西隆高原的北部前沿，可能是由于印度岩石圈俯冲到亚洲下方的弯曲所致。低速区位于雅鲁藏布江山谷下方约 5-10 公里处，这可能是由喜马拉雅弧碰撞和缅甸弧俯冲产生的 NE-SW 趋势压缩应力形成的。Kohima 的地壳最厚，位于 IBCZ 的 Naga 逆冲之下，在 25-40 km 深度处观察到 Vp 和 Vs 的高速带。这种异常可能与高速板块有关，从 N-NE 到 S-SW，