Three-dimensional Inversion of Fluid Flow Electromagnetic Method to Visualize Geothermal Fluid Flow

Abstract

Fluid flow electromagnetic (FFEM) method is a new geophysical method to monitor the dynamic behavior of geothermal fluid flow by measuring surface electromagnetic field caused by subsurface fluid flow. The FFEM method is an original method that was invented by Kyushu University. We developed the measurement system of FFEM method to measure electric and magnetic fields simultaneously at the multiple observation points. In order to visualize 3-D dynamic behavior of geothermal fluid flow using a lot of FFEM data, 3-D inversion program was developed. Using the inversion program, we can delineate the location of electric current sources from electric and magnetic data. The fundamental algorithms of modeling and inversion are described and some examples of 3-D modeling and inversion are shown in this paper.