Geophysical evidence for deep subduction of Indian lithospheric plate beneath Eastern Himalayan Syntaxis
喜马拉雅东构造结岩石圈板片深俯冲的地球物理证据

We conducted broadband seismic observation and MT detection around the Namche Barwa from 2009 to 2010. P wave velocity perturbations down to 300km were obtained and two electrical models were acquired by 2D inversion. There are similar features between electrical models and the corresponding tomographic images by joint interpretation. Our results show that the upper crust of Namche Barwa is separated by IYS and consists of prominent high-velocity and resistive blocks. The mid-lower crust is inhomogenous and characterized by low-velocity and conductive anomaly. The Indian lithospheric mantle has subducted beneath Eurasian plate and its frontier has passed through the Jiali shear zone and reached the Bangong-Nujiang suture; A large-scale low-velocity anomaly is revealed within the Lhasa block beneath the high-velocity plate from 100km to 200km depth, above which the mid-lower crust is an extensive low-velocity conductor. This suggests that there exist channels beneath southeastern Tibetan Plateau favorable to weak and flowable materials exuding towards east and southeast, which gives geophysical evidence for the dynamics mode of deep-subduction of Indian Plate beneath the Namche Barwa.