Structural and Oceanographic Controls on Pockmark Distribution and Morphology in the Northwestern Sicily Offshore: Insights from Seismic and Machine Learning Approaches

Pockmarks, seafloor depressions, provide valuable insights into subsurface fluid migration and geological processes, representing a critical factor in seafloor morphological evolution. This study investigates the distribution and morphology of pockmarks in the Northwestern Sicily offshore (Sicily Straits) by integrating 2D seismic reflection profiles, multibeam bathymetric data, and advanced analytical techniques. Our primary aim is to discriminate actively degassing pockmarks and examine their spatial relationships with geological structures and stress-field-oriented tectonic features.

              While previous studies emphasized the role of subsurface fluid migration mechanisms, our findings highlight a significant correlation between pockmark locations and structural highs, with pockmarks clustering along the flanks of folds demarcated by fault zones. This spatial association suggests that structural elements act as primary conduits for fluid migration, focusing fluid escape at specific seafloor locations.

              To achieve these insights, we employed machine learning-based seismic attribute analysis and bathymetric processing. One toolchain automatically extracted seismic anomalies indicative of fluid pathways, such as bright spots, acoustic blanking zones, and gas chimneys. Another toolchain used morphometric wavelength analysis to classify and map pockmarks, enabling detailed morphological and spatial characterization.

              Our results reveal that while oceanographic processes such as the Adventure Bank Vortex play a role in shaping the morphology of elongated pockmarks, their spatial distribution is primarily influenced by structural controls. These findings refine the previous interpretations and provide a more nuanced understanding of the interplay between tectonic and oceanographic factors in shaping pockmark fields. This study underscores the importance of integrating structural, morphometric, and fluid-migration analyses to comprehensively assess pockmark dynamics and their implications for seabed evolution and geohazards.