Interpretation of potential field data using fast sigmoid function filter – A case study: Gole-Gohar mine, Kerman Province, Iran

Determination of the edges of geological structures such as dykes, faults, salt domes, etc., is one of essential issues in the interpretation of gravity and magnetic data. In this paper, to determine the edges and lateral boundaries of buried geological structures, a filter is introduced that has been obtained by combining fast sigmoid function and the horizontal and vertical derivatives of the total horizontal gradient. For this purpose, first, the efficiency and capability of the fast sigmoid function is investigated on gravity and magnetic synthetic models obtained from prismatic buried sources and Bishop synthetic magnetic model, and then, the ability of the filter compared to standard filters such as total horizontal gradient (THDR), tilt angle (TDR), theta map (TM) and tilt angle of total horizontal gradient (TAHD), on the gravity and magnetic field data from Gol-e-Gohar mine located in Kerman Province is investigated. For both synthetic and field models, the fast sigmoid function method has better quality and resolution than other edge enhancement filters and is capable of simultaneously determining the boundaries of gravity and magnetic sources. Therefore, the fast sigmoid function filter can reliably be used in the qualitative interpretation of potential field anomalies and helps to identify the edges of subsurface structures.