Seismic ambient noise is nowadays widely used in geophysics to characterize the subsoil structure. They are convenient, practical, and low-cost tool to provide reliable information about the underground structure especially in urbanized area. In this paper, seismic ambient noise measurements are used to study the subsoil properties at a site in the south of Tehran. Single station RayDec (Random Decrement method) and three-component F–K (frequency–wavenumber) array methods are considered. RayDec is scrutinized more precisely through applying different signal processing parameters. In this regard, a set of synthetic seismic ambient noise is produced for a 1-D earth structure very similar to what already is known in the south of Tehran, near to the place of seismic ambient noise measurements in an array of stations. The effects of applying different filters and triggering conditions on ellipticity curves are studied. Then, resultant ellipticity curves are compared to the theoretical curve obtained from known earth model to find the suitable parameters. The resultant ellipticity curve plus the dispersion curve obtained from F–K are used as targets in the inversion process. The shear wave velocity and the depth of bedrock at the site in the south of Tehran are estimated about 2200 ± 200 m/s and 700 ± 70 m, respectively. They show agreement with geological evidences and also the previous studies in this site.

中文翻译：

---

提取椭圆度曲线以获取剪切波速度剖面的 RayDec 参数分析：德黑兰南部的案例研究

地震环境噪声如今在地球物理学中被广泛用于表征底土结构。它们是一种方便、实用且成本低廉的工具，可以提供有关地下结构的可靠信息，尤其是在城市化地区。在本文中，地震环境噪声测量用于研究德黑兰南部一个地点的底土特性。考虑了单站 RayDec（随机递减法）和三分量 F-K（频率-波数）阵列方法。通过应用不同的信号处理参数，可以更精确地检查 RayDec。在这方面，为一维地球结构产生一组合成地震环境噪声，该结构与德黑兰南部已知的非常相似，靠近一系列台站中的地震环境噪声测量地点。研究了应用不同滤波器和触发条件对椭圆率曲线的影响。然后，将得到的椭圆率曲线与从已知地球模型获得的理论曲线进行比较，以找到合适的参数。得到的椭圆度曲线加上从 F-K 获得的色散曲线被用作反演过程中的目标。德黑兰南部场地的剪切波速度和基岩深度估计分别约为 2200±200 m/s 和 700±70 m。它们与地质证据以及该地点以前的研究一致。得到的椭圆度曲线加上从 F-K 获得的色散曲线被用作反演过程中的目标。德黑兰南部场地的剪切波速度和基岩深度估计分别约为 2200±200 m/s 和 700±70 m。它们与地质证据以及该地点以前的研究一致。得到的椭圆度曲线加上从 F-K 获得的色散曲线被用作反演过程中的目标。德黑兰南部场地的剪切波速度和基岩深度估计分别约为 2200±200 m/s 和 700±70 m。它们与地质证据以及该地点以前的研究一致。