2D interpretation of self-potential data using Normalized Full Gradient, a case study: galena deposit

This paper describes usage of the Normalized Full Gradient (NFG) method to selfpotential (SP) data. It can be used to estimate location, depth to the top, and center of the deposit. One of the important parameters to estimate, the accurate shape of the deposit, is true selection of the harmonic number. In this paper, the correct harmonic number is determined by the trial-and-error method, and then this method would be tested for noisecorrupted synthetic data. As a consequence of using the NFG method to anomalies of simple geometric-shaped models including vertical sheet and inclined sheet, the underground structures are found very close to their actual locations. In order to see the capability of the method to localize multi-object simultaneously, the NFG method could accurately indicate location of both constructed structures along a profile. Subsequently, reasonable results are acquired after corrupting the anomalies with noise. Finally, the NFG is applied to SP data from a galena deposit located in the NW of Iran, Khalf village. Geological interpretation of the study area confirmed occurrence of a Galena vein. The vein deposit can be simulated by a simple sheet model. After implementation of the method, a general view of the deposit structure is obtained and it helped us to get a fast interpretation. Final result of this method showed that the deposit began from the surface to approximately less than 50 m.