Receiver function inversion and structural analysis in the West Kunlun

Abstract：The seismic profile from Yecheng-Gar (Shiquanhe) in the West Kunlun on the Qinghai-Tibet Plateau deployed by the Sino-French joint project traversed major structural units in the West Kunlun tectonic syntax. Through a receiver function analysis of three-component P wave data recorded by 36 stations for 128 teleseismic events, the authors obtained the variation trend of the receiver functions with the azimuth and epicenter distance for these stations and analyzed its relationship with crustal structure. The shear wave velocity distribution in the upper 120 km of the crust ａｎｄ ｕｐｐｅｒ ｍａｎｔｌｅ was obtained by the inversion of average receiver functions at various stations. On that basis, combined with interpretations of geological structure, the phenomenon that the inclined surface of the Kangxiwar fault becomes gradually nearly upright and then drags southward slightly has been found, which is markedly manifested by sediments of the Tarim foreland basin thrustｅ structures, and in addition it is also inferred that there is décollement beneath the basin. The Bangong Co-Nujiang suture also has traces of northward subduction. So it is deduced that the long distance effect of India-Tibet collision is hindered at the West Kunlun, and the stress is released by subsidiary faults at the surface and a foreland structural model of basin sediments is constructed.