This study collected waveform data from 50 regional seismic events recorded by 114 broadband seismic stations located at the northeastern margin of the Tibetan Plateau.Utilizing the full-waveform inversion method based on the quadratic Wasserstein(W2)metric and operating within the 10～100 s frequency band,we obtained high-resolution crust-mantle structural images for the region.Our findings indicate that the mid-lower crust of the Qinling orogenic belt exhibits high-velocity characteristics,suggesting that the plateau's deep crustal weak material has not infiltrated this area.However,the deep crust spanning from the Songpan-Garze Block across the Kunlun Fault to the Qinling-Qilian Block presents low S-wave velocity,positive radial anisotropy(VSH＞Vsv),and an anomalous high Poisson's ratio,hinting at the horizontal flow of deep crustal materials.In contrast,the central part of the Qinling-Qilian Block exhibits deep crustal high-velocity features accompanied by negative radial anisotropy(VSH＜VSV)and a low Poisson's ratio anomaly,implying a cessation of crustal flow in this location.Furthermore,the Longriba Fault presents as a distinct structural anomaly boundary within the deep lithosphere,suggesting it might delineate the leading edge where the Yangtze Block is wedging westward into the Tibetan Plateau.
关键词
青藏高原东北缘/Wasserstein度量/波形反演/地壳流/径向各向异性/泊松比
Key words
Northeastern Tibetan Plateau/Wasserstein metric/Waveform inversion/Crustal flow/Radial anisotropy/Poisson's ratio
维普
万方数据