首页|3D shear wave velocity and azimuthal anisotropy structure in the shallow crust of Binchuan Basin in Yunnan,Southwest China,from ambient noise tomography

3D shear wave velocity and azimuthal anisotropy structure in the shallow crust of Binchuan Basin in Yunnan,Southwest China,from ambient noise tomography

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3D shear wave velocity and azimuthal anisotropy structure in the shallow crust of Binchuan Basin in Yunnan,Southwest China,from ambient noise tomography
The Binchuan Basin in northwest Yunnan,southwest China,is a rift basin developed at the intersection of the Red River Fault and Chenghai Fault,where historical earthquakes have occurred.Understanding the fine velocity structure of the shallow crust in this region can help improve earthquake location accuracy and our understanding of the relationship between fault zone structures and fault slip behaviors.Using the continuous waveform data recorded by 381 dense array stations in 2017,we obtained 7 915 Rayleigh-wave phase velocity dispersion curves in the period band of 0.2-6 s from ambient noise cross-correlation functions after rigorous data processing and quality control.We determined 3D isotropic and azimuthally anisotropic shear wave velocity models at depths above 6 km in the shallow crust based on the direct surface wave azimuthal anisotropic tomography method.The isotropic model reveals a strong correspondence between the S-wave velocity structure at depths of 0-1 km and the regional topography and lithology.The Binchuan depocenter,Zhoucheng depocenter,Xiangyun Basin,and Xihai Rift Basin are primarily composed of Quaternary deposits,which show low-velocity anomalies,while the regions with the Paleozoic shale,limestone,and basalt exhibit high-velocity anomalies.The nearly N-S orien-tation of fast directions from azimuthal anisotropy models are mainly controlled by the active Binchuan Fault with N-S strike as well as the NNW-oriented primary compressive stress.

Binchuan BasinAmbient noise tomographyShallow crustal structureAzimuthal anisotropy

Jing Wang、Huajian Yao、Ying Liu、Baoshan Wang、Weitao Wang

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Laboratory of Seismology and Physics of the Earth's Interior,School of Earth and Space Sciences,University of Science and Technology of China,Hefei,230026,China

Mengcheng National Geophysical Observatory,University of Science and Technology of China,Mengcheng,233500,China

Institute of Geophysics,China Earthquake Administration,Beijing,100081,China

Binchuan Basin Ambient noise tomography Shallow crustal structure Azimuthal anisotropy

2024

地震研究进展(英文)
中国地震局

地震研究进展(英文)

影响因子:0.032
ISSN:2096-9996
年,卷(期):2024.4(4)