MODELING THE 2D TERRAIN EFFECT ON MT BY THE BOUNDARY-ELEMENT METHOD

The boundary-element method is used to model the 2D terrain effect on the magnetotelluric (MT) held. Firstly, the boundary-value problem of a 2D magnetotelluric held is transformed into an integral equation pro blem by using Green's theorem. Then the boundary-element method is use d to solve the integral equation and to obtain the MT field and its no rmal derivative on the terrain. From these values, the apparent resist ivity can be calculated. Compared with the finite-element method, the boundary-element method is simpler in element division and the initial data preparation. The configuration of a terrain divided by the bound ary-element method is more consistent with the practical terrain. The method proposed in this paper can be run on a microcomputer, so that i t can be used in the held.