Abstract:Based on the boundary value problem of partial differential equation of the two-dimensional magnetotelluric (MT) forward modeling meet, the detail algorithm of finite element method deduced by the rectangular grid subdivision and cell biquadratic interpolation method were used to solve the electromagnetic problems both in TE and TM polarization mode. By using the basic theory of inversion, the solving ill-posed problem regularization method was applied to the least-square optimization approach, and the most smoothness constrained least square regularization inversion objective function was gotten, then a completed two-dimensional magnetotelluric forward computational program was written by Matlab. This program was applied on high/low resistance geoelectric model and Sasaki model, the inversion cross-sectional profiles of TE mode, TM mode and TE&TM joint inversion model separately were plotted. Compared the inversion results with the original models, TE mode inversion profile has higher vertical resolution, TM mode has higher lateral resolution, TE&TM joint inversion is superior to the single inversion of polarization mode. At the same time, MT biquadratic interpolation finite element forward modeling and least-square regularization inversion algorithm are proved to be effective and feasible.

Key words: magnetotelluric; finite element method; forward simulation; least-squares regularization joint; joint inversion