Estimating the influence zone of a vertical magnetic dipole in aerial prospecting

We consider the direct problem of aerial electric sounding for a layered medium with a vertical cylindrical anomaly. We determine the minimum size of the anomaly when it is indistinguishable from an infinite layer of the same conductivity. The integral equation is solved by the integral current method. The concept of apparent conductivity is introduced for sounding problems using a magnetic dipole. The calculations support the conjecture of the locality of aerial sounding and prove the high efficiency of the integral current method for such problems.