| 青藏高原中部INDEPTH-III剖面低速层研究 |
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| 关键词:Tibetan Plateau Bangong Co–Nujiang Suture receiver function analysis low velocity zone |
| 基金项目:国家自然科学基金项目(编号: 41761134094; 41574086; 41274095);国家重点研发计划项目(编号: 2016YFC0600301; 2018YFC0604102);中国地质调查局地质调查项目(编号: DD20190015) |
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| A Study of the Low Velocity Layer along INDEPTH-III Profile in Central Tibetan Plateau |
| The northward collision and subduction of the Indian continental plate led to the rapid uplift of the Tibetan plateau. As a result, the material composition and tectonic evolution in the plateau are the most complex, and hence the distribution characteristics and tectonic origin of the low-velocity strata are still unclear. The broad-band seismic observations are relatively high on both sides of the Bangong Co–Nujiang Suture zone (BNS) in the central part of northern Tibetan Plateau, which provides a good condition for investigating the distribution of low-velocity layers. In this paper, the authors selected the teleseism data recorded by INDEPTH-III broadband seismic stations deployed on both sides of the BNS to the receiver function analysis. The authors improved the signal-to-noise ratio through time-frequency domain phase filtering, and obtained the one-dimensional S-wave velocity structure characteristics under each station by use of the nonlinear inversion method of the complex spectrum ratio of the receiver function. The results obtained by the authors show that a discontinuous low velocity layer with the depth of 20~40 km is widely distributed within the crust beneath both sides of the BNS, and low velocity layers also appear in 0~15 km nearby the subsurface. Comparisons show that the distribution pattern of low-velocity layers in the upper crust is mainly related to the surface regional structure, like east-western trend thrust fault zone and surface sediments, while low-velocity layers in the middle and lower crust not only are constrained by the boundary of the terrane but also possibly related to the Tibetan Plateau uplifting. |
| NIU Xiao,ZHENG Hong-wei,HE Ri-zheng,LI Yu-lan,YAN Jiang-yong,LI Zong-xu.2021.A Study of the Low Velocity Layer along INDEPTH-III Profile in Central Tibetan Plateau[J].Acta Geoscientica Sinica,42(1):74-84. |
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