Estimation of depth of buried conductive sphere from electromagnetic induction anomaly data using linearization process

Abstract

In this paper, we have developed a least-squares minimization method to estimate the depth of a buried conducting sphere using electromagnetic induction (EMI) data. This approach is basically based on the solving a set of algebraic linear equations to estimate the depth of sphere embedded in an insulating media. In electromagnetic induction method, the transmitter coil produces the incident magnetic and electric fields that obey the Maxwell’s equations. In the receiver coil, the received response is created in two modes—eddy-current mode (V _ec) derived from the perfectly conductor placed in the shallow depth and another mode called current-channeling response (V _cc) which depends on the conductivity of the medium. As expected, these responses differ depending on the direction of the incident field related to the receiver coil’s axis. In our case, the transmitter coil’s axis is parallel to the ground surface, and only the eddy-current response is measured in the receiver coil. The validity of this new method is demonstrated through studying and analyzing synthetic EMI anomalies, using simulated data generated from a known model with different random error components and a known statistical distribution.