Pn wave tomography of eastern Tibetan plateau
Pn wave tomography of eastern Tibetan plateau
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发表时间：
2013
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通讯作者：
Hyun-Chul Wang;T. Hearn;Ys Chen;S. Pei;Yongge Feng;H. Yue;G. Jin;Sy Zhou;Y-B. Wang;Z. Ge;Jy Ning;E. Sandvol;J. Ni
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作者：
Hyun-Chul Wang;T. Hearn;Ys Chen;S. Pei;Yongge Feng;H. Yue;G. Jin;Sy Zhou;Y-B. Wang;Z. Ge;Jy Ning;E. Sandvol;J. Ni
该地区的平均Pn速度为8.1 km/s，但从7.8 km/s到8.3 km/s不等。这包括龙门山逆冲构造西北、昆仑断裂东部和祁连山东部以下的极低Pn速度带。在班公-怒江缝合带东端（以31-33°N， 90-98°E为界）有一个高Pn速度区。它可能是印度地下盾的一部分。祁连山和昆仑山之间的区域也具有高Pn速度的特征，并有几个极高速度带。这包括柴达木盆地和共和盆地两个高速构造。这些特征可能对应于在特提斯海洋关闭期间增加的克拉通碎片，这些碎片阻碍了高原向北的生长，但没有停止。东北高原地壳厚度明显减小，区域内也存在横向变化。
Data from recent INDEPTH IV and other broadband deployments in Tibet are used to invert for crustal delays and Pn velocities beneath the eastern Tibetan Plateau and surrounding regions.The average Pn velocity for the region is 8.1 km/s but varies from 7.8 to over 8.3 km/s.Generally low Pn velocities are found in the northeastern Tibet in the Qiangtang and Songpan-Garze terrains.This includes a zone of very low Pn velocity northwest of the Longmen Shan thrust,along the eastern Kunlun fault,and beneath the eastern Qilian Shan.A region of high Pn velocity underlies the eastern end of the Bangong-Nujiang Suture(bounded by 31—33°N;90—98°E).It could represent part of the underthrusting Indian shield.The region between the Qilian Shan and Kunlun Shan is also characterized by high Pn velocity with several zones of extremely high velocity.This includes two high velocity features beneath Qaidam basin and Gonghe basin.These features may correspond to cratonic fragments that accreted during the closure of the Tethys Ocean and have impeded,but not stopped,the northward growth of the plateau.The station delays show the thickest crust is beneath Tanggula Shan in central Tibet and should be the result of the internal deformation within Qiangtang terrain due to the collision of Indian and Eurasia plates.There is a significant decrease of crustal thickness in the northeast plateau and lateral variation also exists within the region.