A Novel Filter “ImpTAHG” for Edge Detection and a Case Study from Cambay Rift Basin, India

A magnetic anomaly combines the response of various rocks with magnetic susceptibility that eventually gives fundamental information regarding the structure and dimensions of the geological features hidden underneath. Over the years, edge detection filters have successfully separated geological structures based on the sharp discontinuity in the rock's susceptibility. Most of the filters have limitations related to (1) being unable to detect the edges of the sources simultaneously at shallow and deeper depths, (2) the response from weak and intense data being unbalanced and (3) failing to detect anomaly sources at greater depths. The present study introduces a new edge enhancement filter called the Improvised Tilt Angle of Horizontal Gradient, abbreviated as “ImpTAHG”, that uses the hyperbolic tangent function involving the derivatives of the tilt angle of the horizontal gradient. Synthetic data is used to demonstrate the filter's efficacy by comparing the response with various conventional filters. The filter avoids spurious edges and provides sharper and accurate edges from shallow, deeper, thinner and thicker sources. If the data is noisy and dominated by non-vertical magnetization, the interpreter may have to opt for upward continuation and reduction to magnetic pole transformation, respectively. The filter is applied on the aeromagnetic data over the Cambay rift basin, India, and successfully mapped the unidentified structural features and major tectonic blocks buried under sediment cover. The ImpTAHG filter proves to give a better prospect in the interpretation of magnetic data.