Abstract The continental collision between the Arabian and Eurasian plates plays an important role in the geodynamical evolution of the Zagros and Iranian plateau. In order to investigate the upper mantle structure across the collision zone, we calculated the absolute and relative shear-wave velocity structure along a dense and long temporary seismic profile in NW Iran. The probabilistic 1-D absolute shear-wave velocity (Vs) depth profiles beneath 23 seismic stations were calculated using a trans-dimensional joint inversion approach of P-wave coda together with the Rayleigh wave phase and group velocity dispersion data. These 1-D models are then interpolated to obtain a 2-D Vs model along the profile. In addition, we used a nonlinear teleseismic tomography method to determine shear wave velocity variations beneath 44 seismic stations. Both the absolute and relative velocity models, obtained by different data sets and methods, show a thick (>150 km) high-velocity anomaly beneath the northern part of the Zagros, which could be the thickened Zagros lithosphere associated with continental shortening. A relatively thin lithosphere (~80 km) and lower S-wave velocity beneath Central Iran may suggest a weakened Iranian mantle lithosphere by upwelling of the hot asthenosphere following slab break-off. The presence of a thickened lithosphere beneath the Zagros implies that the Arabian-Eurasian convergence is accommodated mainly as shortening in the mantle lithosphere beneath the Zagros, rather than underthrusting beneath Central Iran. A narrow low-velocity corridor between the Zagros lithosphere and overriding plate (Central Iran), south of the Sanandaj-Sirjan Zone (SSZ), probably due to delamination of the subducting Arabian lithosphere from the Zagros lower crust, likely prohibits transferring stress from the Zagros lithosphere to Central Iran, causing less deformation in the SSZ which is the edge of the overriding plate.

中文翻译：

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非线性远震层析成像和贝叶斯蒙特卡罗联合反演面波频散和远震纵波尾波揭示的扎格罗斯北部碰撞带下上地幔横波速度结构

摘要 阿拉伯板块与欧亚板块的大陆碰撞对扎格罗斯和伊朗高原的地球动力学演化具有重要作用。为了研究跨越碰撞带的上地幔结构，我们计算了沿伊朗西北部密集而长的临时地震剖面的绝对和相对横波速度结构。使用纵波尾波的跨维联合反演方法以及瑞利波相位和群速度频散数据计算了 23 个地震台站下方的概率一维绝对横波速度 (Vs) 深度剖面。然后对这些一维模型进行插值以获得沿剖面的二维 Vs 模型。此外，我们使用非线性远震层析成像方法来确定 44 个地震台站下方的剪切波速度变化。通过不同数据集和方法获得的绝对和相对速度模型都显示了扎格罗斯北部下方厚厚（>150 公里）的高速异常，这可能是与大陆缩短相关的扎格罗斯岩石圈增厚。伊朗中部下方相对较薄的岩石圈（~80 公里）和较低的 S 波速度可能表明，由于板块断裂后热软流圈上涌，伊朗地幔岩石圈减弱。Zagros 下方增厚岩石圈的存在意味着阿拉伯-欧亚辐合主要是作为 Zagros 下方地幔岩石圈的缩短而容纳的，而不是伊朗中部下方的下冲。Zagros 岩石圈和上覆板块（伊朗中部）之间的狭窄低速走廊，位于 Sanandaj-Sirjan 区（SSZ）以南，