地质学报2025，Vol.99Issue(5)：1508-1522,15.DOI:10.19762/j.cnki.dizhixuebao.2023463
基于密集线性台阵地震被动源成像的渭河盆地西缘精细沉积结构研究
Study of the fine-scale sedimentary characteristics in the western margin of the Weihe basin using passive seismic imaging with a dense linear array
摘要
Abstract
In order to investigate the subsurface fine structure and sedimentary characteristics of the key areas with high earthquake risk in the western margin of the Weihe basin,we deployed a dense linear array consisting of 254 short-period three-component seismometers with an average station-spacing of 200 meters in this study,which collected data for 30 days.We calculate the vertical component cross-correlation of the ambient noise,apply the recently developed extended range phase shift method to extract the fundamental mode Rayleigh wave dispersion curves ranging from 3 Hz to 3.3 s,and then invert for high-resolution shear wave velocity structure down to the depth of 2.5 km beneath the dense linear array.Additionally,using the collected three-component seismic noise,we apply the horizontal to vertical spectral ratio(HVSR)method to calculate peak frequencies,and then use an empirical relationship to estimate the thickness of sedimentary layers in the Weihe basin.The tomographic results show horizontal pattern with a high-low-high velocity variation,corresponding to the uplift-depression-uplift geological structure in this sedimentary basin.The result also clearly delineates three major faults and two geological structural units in the region,consistent with the profile obtained by active seismic imaging.The result from HVSR reveals that the sedimentary layers are relatively thick and exhibit a distinct and complete stratigraphic sequence deposited in the Holocene,Neogene,and Quaternary periods in the Cenozoic.A comprehensive analysis integrating results from ambient noise tomography,HVSR and active-source imaging suggests none of the three major faults beneath the 2D array penetrates through the Quaternary formation in this region.This study shows that the extendedrange phase shift and the HVSR methods based on seismic ambient noise are effective in characterizing structures in sedimentary basins.关键词
渭河盆地/沉积结构/背景噪声成像/拓距相移法/场地放大效应Key words
Weihe basin/sedimentary characteristics/ambient noise tomography/extended range phase-shift method/site amplification factor引用本文复制引用
徐勇,邓宝,田晓峰,倪红玉,段永红,肖本夫,李俊伦..基于密集线性台阵地震被动源成像的渭河盆地西缘精细沉积结构研究[J].地质学报,2025,99(5):1508-1522,15.基金项目
本文为国家重点研发计划课题(编号2018YFC1503205,2021YFC3000602)、国家自然科学基金项目(编号42374073)和中国地震局地震科技星火计划项目(编号XH21050)联合资助的成果. （编号2018YFC1503205,2021YFC3000602）
