THREE-DIMENSIONAL RAPID RELAXATION INVERSION FOR THE MAGNETOTELLURIC METHOD
大地电磁法三维快速松弛反演

The crucial step in doing 3D inversion for the magnetotelluric method is to find an effective way to calculate the sensitivity matrix. By detailedly analyzing the expressions of 3D impedences, Frechet kernel functions are derived for 3D case. Defining the object function to smooth the 3D electrical structures, we finally obtained the iteration procedure of 3D Rapid Relaxation Inversion (RRI) for the minimum structure. The 3D RRI algorithm is tested by a synthetic data set with added Gaussian noise of 1 %. The designed models are 2d prism and 3D prism. The inverted resistivity models fit the true models well. The 3D RRI algorithm is also tested on the Kayabe data, which were collected in Kayabe area of Japan for the purpose of prospecting geothermal resource. Tests results show that our 3D RRI inversion algorithm works well on a PC.