小尺度直角坐标系台阵面波走时三维直接成像方法  

A new small-scale three-dimensional direct surface wave travel-time tomography method based on the Cartesian coordinate system

作　　者：王华明 胡景 邵广周[1] 高级[4] 李兴旺 黄宇奇 白超英[1] 张海江[4] WANG HuaMing;HU Jing;SHAO GuangZhou;GAO Ji;LI XingWang;HUANG YuQi;BAI ChaoYing;ZHANG HaiJiang(School of Geological Engineering and Geomatics,Chang'an University,Xi'an 710054,China;Anhui Zhibo Opto-Electronic Technology Co.,Ltd.,Hefei 230088,China;National Engineering Research Center of Offshore Oil and Gas Exploration,Beijing 100028,China;School of Earth and Space Sciences,University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]长安大学地质工程与测绘学院,西安710054 [2]安徽至博光电科技股份有限公司,合肥230088 [3]海洋油气勘探国家工程研究中心,北京100028 [4]中国科学技术大学地球和空间科学学院,合肥230026

出　　处：《地球物理学报》2025年第3期898-911,共14页Chinese Journal of Geophysics

基　　金：国家自然科学基金青年项目(42104051,42304060);中央高校基本科研业务费专项(300102262103);国家自然科学基金面上项目(42174176)联合资助.

摘　　要：面波频散成像对于研究不同尺度的地下介质横波速度结构有着重要作用.近年来发展的面波走时直接成像(Direct Surface wave travel-time Tomography,DSurfTomo)算法,由于其提高了频散数据的利用率以及考虑地下不均匀介质结构的横向相关性,已被广泛地应用到不同尺度(数公里至上千公里)的三维横波速度结构研究中.一般地,对于探测深度3 km范围内的小尺度结构成像(如城市规划、矿产勘探),通常采用独立平面直角坐标系.然而,DSurfTomo是基于球坐标系下的快速行进法进行理论面波走时计算与射线追踪,其比较适应于区域性的地下结构成像研究.为了将DSurfTomo拓展到更小尺度的研究区,本文发展了一种基于直角坐标系的面波走时三维直接成像算法,数值实验表明其能够应用于更小的台阵孔径(100 m).通过山西阳泉矿区一个实际小尺度台阵数据的对比实验,验证了新方法的有效性.Seismic tomography methods based on surface wave dispersion curves have been instrumental in investigating subsurface shear wave velocity structures at different scales.In recent years,the direct surface wave travel-time tomography(DSurfTomo)algorithm has been widely applied to solve three-dimensional shear wave velocity structures at scales ranging from several kilometers to thousands of kilometers.This is attributed to its enhanced utilization of seismic dispersion data and incorporation of horizontal correlation constraints for heterogeneous media.Generally,for small-scale seismic tomography with exploration depths reaching up to 3 km,such as in urban planning and mineral exploration,a local Cartesian coordinate system is employed for velocity model construction.However,DSurfTomo relies on the fast-marching method within a spherical coordinate system to calculate theoretical surface wave travel-times and perform seismic ray-tracing,making it more suitable for regional scale studies.To adapt DSurfTomo to smaller scales,we have developed a three-dimensional direct tomography algorithm for surface wave travel times based on the Cartesian coordinate system.Numerical experiments demonstrate that the newly proposed algorithm can be effectively applied to a smaller seismic array apertures as small as 100 meters.The validity of the new DSurfTomo program has been confirmed using actual surface wave dispersion data from a small-scale seismic array deployed in a mine in Yangquan,Shanxi province.

关 键 词：面波层析成像 面波直接反演法 DSurfTomo 频散曲线 小尺度 

分 类 号：P315[天文地球—地震学]