Inversion of the wideband and high frequency electromagnetic data
宽带高频电磁场数据反演方法研究

To estimate the underground resistivity and permittivity, the nonlinear least-squares inversion method based on Monte-Carlo algorithms is applied in this paper to inverse the wideband high-frequency electromagnetic (WHFEM) polarization ellipse data. The inversion result indicates that the nonlinear least-squares inversion method works well in the half-space or two-layer earth model. In order to reduce instability and increase convergence speed, the Monte-Carlo algorithm is used for multiple-layer model. In the second part, we also adopt the phasor vectorgraph method for fast inversion of apparent resistivity and permittivity which is useful in geology mapping and constructing the initial model for the least-squares inversion.