MT二维和三维连续介质快速反演

Rapid inversion of magnetotelluric data f0r 2-D and 3-D continuous media

采用有限连续函数集描述二维和三维地电模型，可将MT二维和三维连续介质反演问题转变为泛函的变分问题。通过取泛函的一阶变分线性化，按测点离散化，得到与测点相等的多个小线性方程组。它们在每次迭代中可逐个求解，而灵敏度矩阵元素则可采用一维等效模型解析公式快速计算。理论模型和实例表明，这一方法具有计算量小、稳定和快速收敛、反演效果好、适合于解决大型反演问题等特点。

The inversion problem of 2-D and 3-D magnetotelluric data in continuous medium can be changed into fonctionelle variational problem by using finite continuous function family to describe 2-D and 3-D geoelectric models. The minor linear equation systems which are as many as field observation stations are derived from both the linearization of the first order variation of fonctionelle and the discretization in terms of observation locations. These minor equation systems may be solved respectively in each iteration,and their sensitivity matrix elements are fast computed by analytic formula of one-dimensional equivalent model-Theoretical and real results say that the method is characterized by small computation,good stability,fast convergence,nice inversion effect and desirable application to mass-computation inversion problem