Interpretation of gravity data using logistic function and total horizontal gradient (LTHG) - A case study: Charak anticline

Determination of the boundaries and edges of gravity anomalies is of particular importance in the interpretation stages of geological and tectonic structures. In this paper, the ability of different edge enhancement filters, such as total horizontal gradient, analytical signal, tilt angle, total horizontal derivative of tilt angle, theta map, normalized total horizontal derivative, and tilt angle of total horizontal gradient to determine the edges of synthetic and real gravity anomalies is examined and compared. Moreover, in this research, another filter based on logistic function and total horizontal gradient filter is introduced. In order to evaluate the ability and quality of the total horizontal gradient logistic filter in determination of the boundaries of gravity anomalies, first, the filter is applied to the synthetic gravity data of prisms having different depths and density contrasts with noise and without noise, and after observing successful efficiency of the filter on the synthetic gravity data, it is applied on the gravity data related to Charak anticline in Hormozgan Province, Iran. Based on the obtained results, it can be concluded that this filter is superior compared to other boundary filters, and the obtained results are in good agreement with the geological information of the study area. Hence, the total horizontal gradient logistic filter can reliably be used in the qualitative interpretation of gravity anomalies. The synthetic gravity model, results and filter algorithm have been prepared in MATLAB program environment.