中文摘要：

给出了电导率分块均匀大地电磁场二维有限元正演算法。该算法采用矩形网格内进一步三角形细化的方式剖分模型，在每个三角形单元内利用线性插值函数来模拟单元内的场值，这样既利用了矩形网格在编程中的方便特性，又通过三角形网格提高了对倾斜接触面及起伏地形的近似程度，而且不明显增加计算量。本文首先通过对一个水平均匀层状模型进行正演，并与解析解对比，验证了本算法的准确性，最后通过对两个较复杂模型的正演，进一步表明了该算法的有效性和可行性。

英文摘要：

A numerical algorithm of the finite element method （FEM） for 2D MT forward modeling with block homogeneous conductivity has been developed in this paper. This algorithm subdivides four triangular lattices by adding two diagonal lines in a rectangular cell, and the total field parallel to strike over triangular elements is computed by linear interpolation. This allows accurate modeling of inclined interface and topographic surface, and writing codes is facilitated with using rectangular mesh. The comparison between the algorithm＇s solution and the analytic solution of one synthetic layered model indicates that the algorithm is accurate. Lastly, application of the algorithm to two more complex synthetic models indicates that the algorithm is effective and feasible.