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瑞雷波成像能够有效的探测近地表的横波速度结构,准确的提取瑞雷波的频散曲线是该技术的关键.F-K变换法是一种常见的提取频散曲线的方法,然而传统的F-K变换法由于受到震源频带范围和介质滤波作用的影响,计算的频散能量通常集中在较窄的频带范围内,其余频带的能量受到压制,因此提取出的频散曲线频带范围较窄,高阶模式不易识别,为了克服这种缺陷,我们提出一种改进的F-K变换法,提高了该方法提取高阶模式频散曲线的能力.在本文中,我们首先介绍了改进的F-K变换法的原理与计算步骤,然后分别利用传统的和改进的F-K变换法对理论模型正演模拟和实际采集的瑞雷波数据进行处理,将两种方法得到的频散能量图进行对比,结果表明改进的F-K变换法能够呈现出分辨率更高的频散信息,保证了高阶模式频散曲线的有效提取.
Rayleigh imaging can effectively detect the near-surface S-wave velocity structure and accurately extract Rayleigh wave dispersion curve is the key to this technique.FK transform is a common method to extract dispersion curve, but the traditional FK Since the transform method is affected by the frequency range of the source and the effect of dielectric filtering, the calculated dispersion energy is usually concentrated in the narrower frequency band and the rest of the frequency band is suppressed. Therefore, the frequency range of the extracted dispersion curve is narrow, In order to overcome this defect, we propose an improved FK transform method, which improves the ability of this method to extract high-order mode dispersion curves.In this paper, we firstly introduce the principle of the improved FK transform method and Then the traditional and improved FK transform method are used respectively to process the forward modeling of the theoretical model and the Rayleigh wave data actually collected, and the energy dispersion energy diagrams obtained by the two methods are compared. The results show that the improved FK transform The method can present a higher resolution of the dispersion information, to ensure the efficient extraction of high-order mode dispersion curve.