Upper crustal azimuthal anisotropy and seismogenic tectonics of the Hefei segment of the Tan-Lu Fault Zone from ambient noise tomography  

作　　者：Cheng Li HuaJianYao Song Luo HaiJiang Zhang LingLi Li XiaoLi Wang ShengJun Ni 

机构地区：[1]State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines,Anhui University of Science and Technology,Huainan Anhui 232001,China [2]School of Earth and Space Sciences,University of Science and Technology of China,Hefei 230026,China [3]Mengcheng National Geophysical Observatory,University of Science and Technology of China,Bozhou Anhui 233500,China [4]Anhui Earthquake Agency,Hefei 230031,China [5]Anhui Huizhou Geology Security Institute Company,Ltd.,Hefei 231202,China

出　　处：《Earth and Planetary Physics》2025年第2期253-265,共13页地球与行星物理(英文版)

基　　金：financially supported by the National Key Research and Development Program of China (2022YFC3005600);the Foundation of the Anhui Educational Commission (2023AH051198);the National Natural Science Foundation of China (42125401 and 42104063);the Joint Open Fund of Mengcheng National Geophysical Observatory (MENGO-202201)。

摘　　要：The Tan-Lu Fault Zone is a large NNE-trending fault zone that has a substantial effect on the development of eastern China and its earthquake disaster prevention efforts. Aiming at the azimuthally anisotropic structure in the upper crust and seismogenic tectonics in the Hefei segment of this fault, we collected phase velocity dispersion data of fundamental mode Rayleigh waves from ambient noise cross-correlation functions of ~400 temporal seismographs in an area of approximately 80 × 70 km along the fault zone. The period band of the dispersion data was ~0.5–10 s. We inverted for the upper crustal three-dimensional(3-D) shear velocity model with azimuthal anisotropy from the surface to 10 km depth by using a 3-D direct azimuthal anisotropy inversion method. The inversion result shows the spatial distribution characteristics of the tectonic units in the upper crust. Additionally, the deformation of the Tan-Lu Fault Zone and its conjugated fault systems could be inferred from the anisotropy model. In particular, the faults that have remained active from the early and middle Pleistocene control the anisotropic characteristics of the upper crustal structure in this area. The direction of fast axes near the fault zone area in the upper crust is consistent with the strike of the faults, whereas for the region far away from the fault zone, the direction of fast axes is consistent with the direction of the regional principal stress caused by plate movement. Combined with the azimuthal anisotropy models in the deep crust and uppermost mantle from the surface wave and Pn wave, the different anisotropic patterns caused by the Tan-Lu Fault Zone and its conjugated fault system nearby are shown in the upper and lower crust. Furthermore,by using the double-difference method, we relocated the Lujiang earthquake series, which contained 32 earthquakes with a depth shallower than 10 km. Both the Vs model and earthquake relocation results indicate that earthquakes mostly occurred in the vicinity of structural boundaries with frac

关 键 词：ambient noise tomography azimuthal anisotropy upper crust seismogenic structure the Tan-Lu Fault Zone Hefei segment 

分 类 号：P315.2[天文地球—地震学]