Detectability by Electromagnetic Sounding Systems

An analysis has been made of the detectability of subsurface layers by the four electromagnetic (EM) depth sounding systems: horizontal coplanar loops, perpendicular loops, vertical coplanar loops, and vertical coaxial loops. For computing the mutual coupling ratios (the EM response function) the linear digital filter method has been used. The linear digital filter method as applied in computing the EM fields has been briefly reviewed. The EM sounding systems have been compared for the relative effectiveness in the mapping of subsurface inhomogeneities.