Modeling of Galvanic Anomalies by Integral Equation Methods.

This article is a summary of a research project carried out at the Laboratory of Economic Geology of the Helsinki University of Technology in the years 1981-1986. The purpose of the project was to develop modelling techniques for galvanic, especially for mise-a-la-masse anomalies. Two different integral equation formulations were used: 1) Fredholm's integral equation of the first kind, based on the equipotential state of the conductors and solved together with the supplementary equations derived from the equation of continuity, and 2) the case of a finite conductivity contrast formulated by means of Fredholm's integral equation of the second kind for the potential. In addition, the characteristics of mise-a-la-masse anomalies were examined in various geological situations. A comparison between mise-a-la-masse anomalies obtained by different measuring procedures was made. The comparison shows that the potential (normalized with respect to the input current) and potential gradient values are the most usable forms of presentation for mise-a-la-masse anomalies.