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本文提出了一种用瑞利波椭圆率的振幅和相位来估计局部地点近地表横渡速度的方法。椭圆率定义为质点运动径向分量与垂直分量的复付立叶谱之比,用各振型的贡献来模拟椭圆率。由一些二分量检波器测定检波器,再对模拟椭圆率做最小平方拟合而实现反演。反演可以提供横波层速度和振型振幅。此法对二层模型瑞利波合成记录做了数值检验。假定只有横波速度是地层的未知量。速度估值表明,随着迭代次数的增加,而迅速收敛于真实速度值。从超过真实速度15％的“初始猜测”值开始,得到4次迭代的计
In this paper, we propose a method to estimate the near-surface transversal velocities of local sites by using the amplitude and phase of the ellipticity of Rayleigh waves. The ellipticity is defined as the ratio of the Fourier component of the particle motion to the vertical component and the ellipticity is modeled using the contribution of each mode. The detector is determined by some two-component geophones, and the least squares fit to the simulated ellipticity is performed to achieve the inversion. Inversion can provide shear wave velocity and mode shape amplitude. This method does a numerical test of the Rayleigh wave synthetic record of the second-layer model. It is assumed that only the shear wave velocity is an unknown amount of formation. Speed estimates show that as the number of iterations increases, the speed converges quickly to the true speed value. Starting with an “initial guess” value exceeding 15% of real speed, a count of 4 iterations is obtained