论文部分内容阅读
瑞雷波在层状介质中传播具有频散特性,利用地震记录中的面波信息,提取面波的频散曲线,反演可以建立近地表的横波速度结构模型。本文建立了一个理论地质模型,理论合成面波地震记录,研究了频率波数域中面波频散曲线的分模态提取,并利用等厚分层阻尼最小二乘反演方法对面波各模态的频散曲线进行了分模态反演和联合反演。反演结果表明:瑞雷波基阶频散曲线的浅层(<10m)反演结果与理论模型吻合最好,一阶高阶频散曲线在15-30m的反演结果与理论模型吻合最好,联合反演在整个深度范围内都可以很好的吻合理论模型,且反演结果的相对误差要低于分模态反演。
The Rayleigh wave propagates in layered media with dispersion characteristics. Using the surface wave information in seismic records, the dispersion curve of surface wave can be extracted. The inversion can establish the near-surface S-wave velocity structure model. In this paper, a theoretical geologic model is established to theoretically synthesize surface wave seismograms. The sub-modal extraction of surface wave dispersion curves in frequency wave number domain is studied. The isoplethial least squares The dispersion curves were modeled by inversion and joint inversion. The inversion results show that the shallow (<10m) inversion of the Rayleigh-wave dispersion curve is in good agreement with the theoretical model, and the first-order high-order dispersion curve coincides with the theoretical model at 15-30m Well, the joint inversion can well fit the theoretical model in the entire depth range, and the relative error of the inversion results is lower than that of the sub-modal inversion.