Structural delineation of the South Caspian Basin using edge enhancement techniques: Application of the Improved Logistic filter to gravity data

The South Caspian Basin, positioned within the dynamic Alpine-Himalayan orogenic belt, is distinguished by its intricate geological architecture, featuring a sedimentary cover exceeding 20 km and substantial lateral fluctuations in Moho depth. Due to the presence of these deep, massive geological bodies, standard potential field maps frequently fail to resolve fine tectonic nuances. However, the gravitational signals from deep structures often mask subtle features, creating ambiguities in interpreting the regional deformation. For the first time, we utilize the Improved Logistic (IL) filter on Bouguer gravity anomalies to clarify these structural uncertainties and accentuate density contrasts that are otherwise obscured in conventional datasets. The results of our analysis uncovered a complex network of lineaments, predominantly trending NE-SW and WNW-ESE, which provide a multi-scale perspective on the basin's tectonic framework. We successfully highlighted critical tectonic boundaries, such as the Turkmenbashi-Makhachkala fault, and corroborated the segmentation of major uplift zones like Godin and Safidrud. We believe that the Improved Logistic filter acts as a powerful mechanism for revealing subsurface architecture in basins blanketed by thick sedimentation, offering a refined structural model for hydrocarbon exploration and seismotectonic assessment in this complex region. Compared to standard gradient methods, this technique effectively equalizes the gravitational response from varying depths to better interpret deformation mechanisms driven by ongoing plate convergence.