The surface impedance anomaly resulting from a subsurface, infinitely long conductive wire

The change in surface impedance caused by the fields generated by an infinitely long, subsurface wire located in a homogeneous lossy medium (e.g., the Earth) is investigated experimentally and numerically. Sets of curves illustrate the variation in the horizontal electric field, the horizontal magnetic field, and the surface impedance as a function of conductor depth. The half-width at half-amplitude (HWHA) can be used as a measure of the lateral dimensions of the anomaly. While the horizontal magnetic field HWHA is equal to the conductor depth, the horizontal electric field HWHA (and so the surface impedance HWHA) varies not only with depth but also with the conductivity of the medium