Abstract We analyzed teleseismic receiver functions of 9 sites to determine the crustal structure beneath the Indo-Burmese subduction region (IBR), which is seismically one of the most active subduction zones of the Indian subcontinent. The receiver function analysis of the primary and reverberated phases allowed us to image the down going Moho beneath the Burmese micro plate parallel to the subducting slab. We observed that this subduction zone is characterized by sharp dip of a thick (˜45 km) crust in the Indian Territory, which steeply bends down to ˜57 km in the Burmese Territory separated by the Churachandpur Mao Fault (CMF). The Imphal valley, located in the central part of the IBR, has a sedimentary thickness of 2.5 km. The Poisson’s ratio values correlate well with the tectonic units comprises the subduction region. We observed high Poisson’s ratio values throughout the region, which reflects bulk mafic to ultramafic crustal composition. Our observations of Poisson’s ratio beneath the IBR reveal that the Indian crust along the IBR is oceanic in nature, which is possibly the Tethyan oceanic crust of Southeast Asia.

中文翻译：

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印缅俯冲区地壳结构评价

摘要 我们分析了 9 个站点的远震接收器函数，以确定印缅俯冲区 (IBR) 下方的地壳结构，该区是印度次大陆地震最活跃的俯冲带之一。初级和混响相的接收器函数分析使我们能够对平行于俯冲板片的缅甸微板块下方向下移动的莫霍面进行成像。我们观察到，这个俯冲带的特征是印度领土厚（约 45 公里）地壳的急剧倾斜，在被 Churachandpur 毛断层（CMF）分隔的缅甸领土上急剧弯曲至约 57 公里。英帕尔河谷位于 IBR 中部，沉积厚度为 2.5 公里。泊松比值与包含俯冲区的构造单元有很好的相关性。我们在整个地区观察到高泊松比值，这反映了大块基性至超基性地壳的组成。我们对 IBR 下方泊松比的观察表明，沿 IBR 的印度地壳本质上是海洋，可能是东南亚的特提斯洋壳。