THE ELECTROMAGNETIC RESPONSE OF A CONDUCTING DISK FOR USE IN AFMAG INTERPRETATION

Abstract

The buried conducting disk has been suggested by Ward et al (1968) as a suitable model for mineralized zones in the interpretation of AFMAG data. Using an integral equation method, we obtained the secondary magnetic field of a thin disk of arbitrary electrical conductivity. From the magnetic secondary field, we then computed AFMAG anomaly tilt‐angle profiles. These profiles in turn were used to construct interpretation diagrams, of the type introduced by Ward et al, for determining the depth of the disk and its thickness‐conductivity product. The interpretation diagrams obtained, which we show to be accurate, differ from those of Ward et al for intermediate values of the disk conductivity. An alternate method of interpretation, based on measurements of the phase difference between the horizontal and vertical magnetic fields, is also presented.