DEFINITION AND APPLICATION OF THE FREQUENCY-EFFECT TRANSFORM FUNCTION TO THE INTERPRETATION OF IP SOUNDINGS

This paper deals with a new method of quantitative interpretation of induced polarization soundings in the frequency‐domain. From the general expression of the apparent frequency‐effect for soundings carried out on a multi‐layered earth the application of Hankel's inversion theorem allows to introduce a new function, called here the “frequency‐effect transform”. The new interpretation method consists of two steps: 1) the inversion of field data to obtain the frequency‐effect transform graph and 2) the analysis of this graph to derive the layering parameters. The first step is performed by means of a slightly revised version of a simple numerical procedure, previously suggested by the author for the inversion of d.c. resistivity sounding data. The second step is carried out by a complete curve‐matching procedure, applied directly on the transform graph. This implies suitable master curves, whose preparation doesn't meet all the mathematical difficulties which are present when preparing master curves of the apparent frequency‐effect function. Copyright © 1979, Wiley Blackwell. All rights reserved