Development of a Three- Dimensional Inversion Program for Magnetotellurics Using Finite Volume and Adjoint State Method

The Finite Volume Method (FVM) is a kind of numerical analysis method that can take into account topography and apply local subdivision cells as the Finite Element Method (FEM). The Adjoint State Method (ASM) can easily calculate the gradient vector of the objective function for the inversion. The author developed a program that applied these methods to 3-D Magnetotelluric (MT) inversion and verified it using test models. As a result, it was confirmed that the program can perform analysis properly and efficiently considering topography and subsurface resistivity heterogeneity.