三维背景噪声数值模拟及频散曲线验证  

Numerical simulation and dispersion curve verification of three⁃dimensional background noises

作　　者：霍科宇 邵广周[1] 王国顺 白帅 吴华[2] HUO Keyu;SHAO Guangzhou;WANG Guoshun;BAI Shuai;WU Hua(School of Geological Engineering and Geomatics,Chang’an University,Xi’an,Shaanxi 710054,China;School of Science,Chang’an University,Xi’an,Shaanxi 710064,China)

机构地区：[1]长安大学地质工程与测绘学院,陕西西安710054 [2]长安大学理学院,陕西西安710054

出　　处：《石油地球物理勘探》2023年第4期847-856,共10页Oil Geophysical Prospecting

基　　金：国家重点研发计划课题“基于高铁震源的地下介质结构高精度成像与反演”(2021YFA0716902);国家自然科学基金项目“黄土盖层缺陷三维瑞利波相速度谱与波形联合反演成像研究”(42174176);“海底节点地震波场模拟与转换波成像方法研究”(41874123)联合资助。

摘　　要：近年来,以人类生产活动产生的振动和天然振动作为震源的背景噪声成像技术逐渐成为研究热点。无论是基于已知模型对背景噪声成像方法以及频散曲线提取方法的有效性进行验证,还是对背景噪声数据采集方式进行参数优化,均需通过波场数值模拟手段获取所需的背景噪声理论合成数据。三维数值模拟是背景噪声成像中的一项重要研究内容。针对背景噪声在时间域和空间域上具有随机性的特点,将随机震源引入三维瑞雷波波场有限差分数值模拟,实现背景噪声数据的有效计算,将模拟得到的噪声记录用基于Aki公式的两道法提取频散曲线并与理论频散曲线对比,以验证噪声模拟的可行性和有效性。理论模型测试结果表明:当震源参数处于合理范围时,合成背景噪声数据频散曲线与理论频散曲线拟合效果良好;同时三维模拟数据提取的频散曲线比二维模拟数据提取精度更高。In recent years,background noise imaging technology using vibrations generated by human production activities and natural earthquakes as the source has gradually become a research hotspot.Whether it is to verify the effectiveness of the background noise imaging method and the dispersion curve extraction method based on the known model,or to optimize the parameters of the background noise data acquisition method,it is necessary to obtain the required theoretical synthetic data of background noises through wave field numerical simulation.Three‑dimensional(3D)numerical simulation is an important research content in background noise imaging.In view of the randomness of background noises in time and space,this paper introduces the random source into the finite difference numerical simulation of the 3D Rayleigh wave field to effectively calculate background noise data.The dispersion curve of the noise recorded by simulation is extracted by the two‑trace method based on Aki formula and compared with the theoretical dispersion curve,so as to verify the feasibility and effectiveness of noise simulation.The test results of the theoretical model show that when the source parameters are within a reasonable range,the dispersion curve of the synthetic background noise data and the theoretical dispersion curve are well fitted;at the same time,the dispersion curve extracted from the 3D simulation data is more accurate than that by the two‑dimensional simulation data.

关 键 词：数值模拟 随机震源 背景噪声 频散曲线 有限差分 

分 类 号：P631[天文地球—地质矿产勘探]