In urban subsurface exploration, seismic surveys are mostly conducted along roads where seismic vibrators can be extensively used to generate strong seismic energy due to economic and environmental constraints. Generally, Rayleigh waves also are excited by the compressional wave profiling process. Shear-wave (S-wave) velocities can be inferred using Rayleigh waves to complement near-surface characterization. Most vibrators cannot excite seismic energy at lower frequencies (<5 Hz) to map greater depths during surface-wave analysis in areas with low S-wave velocities, but low-frequency surface waves ($>1\mathrm{Hz}$) can be extracted from traffic-induced noise, which can be easily obtained at marginal additional cost. We have implemented synthetic tests to evaluate the velocity deviation caused by offline sources, finding a reasonably small relative bias of surface-wave dispersion curves due to vehicle sources on roads. Using a 2D reflection survey and traffic-induced noise from the central North China Plain, we apply seismic interferometry to a series of 10.0 s segments of passive data. Then, each segment is selectively stacked on the acausal-to-causal ratio of the mean signal-to-noise ratio to generate virtual shot gathers with better dispersion energy images. We next use the dispersion curves derived by combining controlled source surveying with vehicle noise to retrieve the shallow S-wave velocity structure. A maximum exploration depth of 90 m is achieved, and the inverted S-wave profile and interval S-wave velocity model obtained from reflection processing appear consistent. The data set demonstrates that using surface waves derived from seismic reflection surveying and traffic-induced noise provides an efficient supplementary technique for delineating shallow structures in areas featuring thick Quaternary overburden. Additionally, the field test indicates that traffic noise can be created using vehicles or vibrators to capture surface waves within a reliable frequency band of 2–25 Hz if no vehicles are moving along the survey line.

中文翻译：

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从地震反射测量和交通诱发的噪声中提取浅S波剖面

在城市地下勘探中，地震勘测主要是在道路上进行的，由于经济和环境的限制，地震振动器可广泛用于产生强烈的地震能量。通常，瑞利波也通过压缩波轮廓分析过程激发。可以使用瑞利波来推断剪切波（S波）的速度，以补充近地表特征。大多数振动器无法在低频（<5 Hz）的情况下激发地震能量，从而在表面波分析过程中在S波速度低的区域绘制更大的深度，但是在低频表面波（$>\mathrm{1个}\mathrm{赫兹}$）可以从交通噪声中提取出来，而这些噪声很容易以少量的额外成本获得。我们已经进行了综合测试，以评估由离线源引起的速度偏差，发现由于道路上的车辆源而导致的表面波频散曲线的相对较小偏差。利用二维反射测量和华北平原中部的交通噪声，我们将地震干涉法应用于一系列10.0 s的被动数据段。然后，将每个段选择性地堆叠在平均信噪比的因果比上，以生成具有更好色散能量图像的虚拟镜头集。接下来，我们使用通过将受控源测量与车辆噪声相结合而得出的色散曲线来检索浅S波速度结构。最大探测深度达到90 m，通过反射处理获得的倒S波剖面和间隔S波速度模型看起来是一致的。数据集表明，使用从地震反射勘测和交通引起的噪声中提取的面波提供了一种有效的补充技术，用于圈定具有厚第四纪覆盖层的区域中的浅层结构。此外，现场测试表明，如果没有车辆沿测量线行驶，则可以使用车辆或振动器来捕获2-25 Hz可靠频带内的表面波，从而产生交通噪声。数据集表明，使用从地震反射勘测和交通引起的噪声中提取的面波提供了一种有效的补充技术，用于圈定具有厚第四纪覆盖层的区域中的浅层结构。此外，现场测试表明，如果没有车辆沿测量线行驶，则可以使用车辆或振动器来捕获2-25 Hz可靠频带内的表面波，从而产生交通噪声。数据集表明，使用从地震反射勘测和交通引起的噪声中提取的面波提供了一种有效的补充技术，用于圈定具有厚第四纪覆盖层的区域中的浅层结构。此外，现场测试表明，如果没有车辆沿测量线行驶，则可以使用车辆或振动器来捕获2-25 Hz可靠频带内的表面波，从而产生交通噪声。