INTERPRETATION OF CSAMT SINGLE-COMPONENT DATA

Abstract

Following the magnetotelluric method, the apparent resistivity of the controlled source audio-frequency magnetotelluric method is usually derived from the ratio of electric field and magnetic field. For CSAMT, as the source power current density is known, both of the electric and magnetic field components are related to the resistivity of the earth. The apparent resistivity can be obtained from the single electric field or magnetic field. In this paper, we put forward the inversion and interpretation methods for component data of CSAMT after analyzing the data features. During the curve fitting inversion, in order to deduct real formation and obtain finer resistivity-depth section, the number of frequency of curves is regarded as the inversion earth layers number. The all-zone electric component apparent resistivity inversion is developed. Then, the phase is introduced into the inversion process to cancel the static offset. The prospecting for water-filled goaf in Shanxi Province suggests that the single component interpretation is useful.