Geophysics and Geophysical Exploration ISSN:1229-1064(Print) 2384-051X(Online) 지구물리와 물리탐사

Development of a modeling technique for accurately interpreting electromagnetic (EM) data is increasinglyrequired. We introduce finite difference (FD) and finite-element (FE) methods for three-dimensional (3D) frequencydomainEM modeling. In the controlled-source EM methods, formulating the governing equations into a secondary electricfield enables us to avoid a singularity problem at the source point. The secondary electric field is discretized using theFD or FE methods for the model region. We represent iterative and direct methods to solve the system of equationsresulting from the FD or FE schemes. By applying the static divergence correction in the iterative method, the rate ofconvergence is dramatically improved, and it is particularly useful to compute a model including surface topography inthe FD method. Finally, as an example of an airborne EM survey, we present 3D modeling using the FD method.