微动多阶瑞雷波SPAC系数反演方法及应用研究  

Microtremor survey method based on inversion of the SPAC coefficient of multi-mode Rayleigh waves and its application

作　　者：徐佩芬[1,2,3] 杜亚楠 凌甦群 游志伟 姚金 张华 XU PeiFen;DU YaNan;LING SuQun;YOU ZhiWei;YAO Jin;ZHANG Hua(Key Laboratory of Shale Gas and Geoengineering,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Innovation Academy of Earth Science,CAS,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;Xiong'an Urban Planning and Design Institute Company Limited,Xiong'an New Area 071700,China;Beijing Zhongkejiao Energy and Environment Technology Company Limited,Beijing 100083,China;Geo-Analysis Institute Company Limited,Tokyo 184-0012,Japan;Guangzhou Metro Design and Research Institute Company Limited,Guangzhou 510010,China)

机构地区：[1]中国科学院地质与地球物理研究所,中国科学院页岩气与地质工程重点实验室,北京100029 [2]中国科学院地球科学研究院,北京100029 [3]中国科学院大学地球与行星科学学院,北京100049 [4]雄安城市规划设计研究院有限公司,雄安新区071700 [5]北京中科吉奥能源环境科技有限公司,北京100083 [6]日本地学数据分析研究所,东京184-0012 [7]广州地铁设计研究院股份有限公司,广州510010

出　　处：《地球物理学报》2020年第10期3857-3867,共11页Chinese Journal of Geophysics

基　　金：广州地铁设计研究院股份有限公司科研项目(KY-2020-013);国家自然科学基金面上项目(41474044);国家自然科学基金重点项目(41330643);中国地质调查局地质调查项目(DD20189132,DD20179611)联合资助.

摘　　要：为充分利用微动信号中基阶和高阶模式瑞雷波,本文研究了基于多阶瑞雷波SPAC系数直接反演的方法.该方法首先基于地层介质响应计算多阶瑞雷波的能量占比,考虑实际观测台阵有限台站个数对SPAC系数影响,正演计算多阶瑞雷波SPAC系数,再采用快速模拟退火算法对其反演以获得地下介质横波速度结构.在此基础上,本文通过数值模拟验证该方法的可靠性,分别选取三种典型地质模型,基于模式叠加算法合成理论微动信号,采用本文方法计算其理论多阶瑞雷波SPAC系数并反演,给出反演结果与真实模型对比.我们将该方法应用于上海中心城区的地质调查中,通过与钻探结果对比,进一步验证该方法的有效性.本文理论与实际应用研究表明,基于多阶瑞雷波SPAC系数直接反演的微动探测方法有助于提高反演结果的可靠性,尤其对含软硬夹层的复杂地层介质,可提高探测精度.To make full use of the information found in the Rayleigh waves which propagate along the earth surface,a microtremor survey method was proposed and studied in this paper,based on the inversion of the SPAC coefficient of multi-mode Rayleigh waves observed in the microtremor signal.This technique provides a useful and reliable option for urban geological investigation by mapping the S-wave velocity structure of the near surface.First,the energy ratios of the multi-mode Rayleigh waves were computed using the medium response of each mode;Then,the SPAC coefficients of the fundamental and higher modes Rayleigh waves were calculated by forward modeling,with the influence of the finite arrays on the SPAC coefficient in practical work being taken into account;Finally,fast simulated annealing algorithm was used to invert the SPAC coefficient to obtain the subsurface shear wave velocity structure.Synthetic microtremor datasets from three typical geological models were studied using the mode algorithm of Herrmann,and compared with the inverted SPAC coefficients from field data.This technique was successfully used in the underground investigation project in downtown Shanghai,and the inversion results from the theoretical data and field data matched well.Our study shows that the microtremor survey method can provide more accurate and high resolution mapping of the near surface,especially for the geological structures with weak or hard interlayers.

关 键 词：微动探测 多阶瑞雷波 SPAC系数反演 快速模拟退火 

分 类 号：P631[天文地球—地质矿产勘探]