超短时线性台阵背景噪声成像技术在浅层地质结构探测中的应用  

Application of ultra-short-time linear array ambient noise imaging technology to detect shallow geological structures

作　　者：敬嘉良 陈国雄[1] 程飞 丹阳 刘江平[4] 徐富文 王德涛 JING JiaLiang;CHEN GuoXiong;CHENG Fei;DAN Yang;LIU JiangPing;XU FuWen;WANG DeTao(State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,China;Faculty of Earth Resources,China University of Geosciences,Wuhan 430074,China;College of Marine Science and Technology,China University of Geosciences,Wuhan 430074,China;School of Geophysics and Geomatics,China University of Geosciences,Wuhan 430074,China;The First Geological Brigade of Hubei Geological Bureau,Daye 435000,China)

机构地区：[1]地质过程与矿产资源国家重点实验室,中国地质大学(武汉),武汉430074 [2]中国地质大学(武汉)资源学院,武汉430074 [3]中国地质大学(武汉)海洋学院,武汉430074 [4]中国地质大学(武汉)地球物理与空间信息学院,武汉430074 [5]湖北省地质局第一地质大队,大冶435000

出　　处：《地球物理学进展》2024年第1期63-76,共14页Progress in Geophysics

基　　金：湖北省地质局科技项目(KJ2020-5,KJ2022-15)资助.

摘　　要：背景噪声地震成像方法已被广泛应用于探测壳幔深部结构;近些年来,该方法在浅地表结构成像中的应用研究也在蓬勃发展,然而近地表场源不均匀等因素导致高频面波信号往往难以准确恢复,以牺牲时间来提高信噪比的观测方式会极大限制其在工程勘查中的应用.本文尝试讨论超短时背景噪声成像技术在浅层地质结构探测中的应用效果.笔者利用湖北应城地区超短时(1 h)线性台阵地震背景噪声记录,使用被动源面波多道分析法从虚拟炮集中提取相速度频散曲线,通过反演获取了浅地表二维横波速度结构.结果表明,利用本文方案可以恢复高信噪比面波信号、获取高信噪比的频散能量以及拾取高精度相速度;反演速度结构与实际测井数据吻合度好,成像结果有效揭示了测区150 m以浅的地层结构,证明了超短时背景噪声成像技术在浅层地质结构调查中具有很大的应用潜力.Ambient Noise Tomography(ANT)techniques have been widely used to image the deep structure of lithosphere,while recent years have also seen great efforts for applying this techniques for shallow subsurface imaging.However,the high frequency surface wave signal is difficult to recover accurately due to the non-uniform near-surface field sources.The scheme for improving the Signal-Noise-Ratio(SNR)at the expense of time will greatly limit the application of ANT in engineering exploration.This paper showcases the application of ultra-short-time ANT techniques in the detection of shallow geological structures.With the ultra-short-time(1 h)linear array seismic ambient noise data recorded in the Yingcheng city of Hubei Province,we used the multi-channel analysis of passive surface waves to extract the phase-velocity dispersion curve from the virtual shot set,and obtained the two-dimensional shear-wave velocity through inversion.The results show that the generated scheme can estimate surface wave signals with high SNR,obtain high-resolution dispersion energy,and pick up high-precision phase velocity.The inversed velocity values are in good agreement with the well logs,and the velocity image effectively reveal the strata structures<150 m in the survey area,which proves that the ultra-short time ANT technology has great potential for detecting the shallow geological structures.

关 键 词：背景噪声 超短时 频散曲线 浅层地质结构 横波速度反演 

分 类 号：P315[天文地球—地震学]