Recording the Vertical Component of the Electric Field in Magnetotelluric Sounding

Abstract —Magnetotelluric sounding (MTS) usually records variations in five components of the electromagnetic field. Interpretation of distorted MT responses of an inhomogeneous earth may be problematic. The problem can be solved by recording additionally the vertical component Ez of the electric field in order to improve the quality of inversion and to gain more information. Currently Ez variations are estimated by measuring voltage on a vertical line immersed in water. The land measurements of this kind require special drilling or using the existing boreholes, which is not always feasible. Otherwise, a circular electric dipole (CED) can be used as a receiver to record the electric field behavior along the vertical component. Its applicability to MT soundings is analyzed in this paper.