近地表隐伏断层地震波场响应特征与初至波成像应用研究
投稿时间:2022-09-26  修订日期:2023-05-20  点此下载全文
引用本文:孙茂锐.近地表隐伏断层地震波场响应特征与初至波成像应用研究[J].地质与勘探,2023,59(5):1043-1053
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孙茂锐 安徽省交通规划设计研究总院股份有限公司安徽合肥 交通运输部公路交通节能与环保技术及装备研发中心安徽合肥 1633043607@qq.com 
基金项目:地球内部多尺度成像湖北省重点实验室开放基金项目(编号:SMIL-2017-10)、安徽省交通规划设计研究总院股份有限公司科研项目(编号:HF220191)联合资助
中文摘要:近地表隐伏断层直接影响工程安全施工。通过构建浅覆盖层下方陡立界面断层数值模型,分析近地表隐伏断层地震波场的传播与转换规律。通过工程实测数据验证了数值模拟波场响应特征的可靠性,并利用初至波走时层析成像技术对地下介质波速进行成像。研究结果表明:(1)初至波转换形成的断点绕射波具有1频率升高、速度突变的特点,可清晰指示测区内断裂带的存在,可作为现场数据采集时断层的直观反映;(2)工程实测中通过原始波形到时、频率信息可初步判断断层的存在,基于射线追踪的初至波层析成像结果与后期钻孔揭露情况基本吻合,说明初至波层析成像在浅层地震勘探中的实用性;(3)接收测线排列内布设震源的方式,两侧震源延拓距离短,无需额外为震源激发提供场地,在工程施工中具有经济、快速、高效的特点,可作为野外复杂地表条件地下浅层结构探测的有效观测系统使用。
中文关键词:隐伏断层 近地表 地震波场 初至波 波场特征 层析成像
 
Response characteristics of seismic wave field for near-surface buried faults and the application of seismic first-break imaging
Abstract:Near-surface buried faults directly affect the safety of engineering construction. This work established a numerical model of steep interface faults under shallow overburden, and analyzed the propagation and transformation law of seismic wave field of near-surface buried faults. The reliability of the numerical simulation of wave field response characteristics was verified by the measured project data, and the tomography technology of the first-break wave travel time was used to image the wave velocity of underground media. The results show that: (1) The diffraction wave of fault points formed by the first-break wave conversion is featured by increasing frequency and sudden velocity changes, which can clearly indicate the existence of the fault zone in the survey area and can be used as an intuitively reflect faults in field data acquisition. (2) In engineering measurements, the existence of faults can be preliminarily judged by the arrival time and frequency information of the original waveform. The first-break wave tomography based on ray tracing is basically consistent with the later drilling exposure, indicating that the first-break wave tomography is practical in shallow seismic exploration. (3) The method of arranging the source in receiving line arrangement has a short extension distance on both sides of the source, and there is no need to provide additional space for the source excitation. It is economic, rapid and efficient in engineering construction, and can be used as an effective observation system for underground shallow structure detection under field complex surface conditions.
keywords:buried fault, near surface, seismic wave field, first-break seismic wave, wave field characteristics, tomography
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