Pre-conditioned seismic attributes applied to deep vintage seismic reflection line: enhancing fault patterns on the Italian CROP-04 .

Reflection seismic is the best active geophysical method to constrain the geometry and kinematics of faults at depth. In some specific areas, seismic profiles derived from industry or from past research programs can be nowadays still used in seismotectonic studies to link the surface faults traces with hypocentral earthquake sources. Deep reflection seismic profiles such as the ones recorded in the framework of  the Italian “CROP” aimed shed light on the deep subsurface structures, despite the high levels of random noise hampering the seismic interpretation. Also the CROP-04 “Agropoli-Barletta”, seismic transect acquired from the Tyrrhenian to the Adriatic Sea across the Southern Apennines fold-and-thrust belt and the foreland system, is strongly affected by random noise. Various geological interpretations based on this data are available in literature, as this seismic profile crosses important active faults such as the Irpinia fault, which produced the destructive 1980 Mw 6.9 earthquake. Aiming to improve the data quality, by reducing the noise, to perform a structural interpretation of its shallower sector, we applied a dedicated workflow encompassing pre-conditioning filters, selected seismic attributes and co-rendered views. Following this workflow we have considerably enhanced the reflection patterns and the overall data interpretability, unveil a dense and complex sets of normal faults, thus imaging tectonic structures which were invisible in the original CROP-04. In addition, the master faults mapped at surface well matches the seismic signature. The reprocessed profile displays also clear low-angle W-dipping thrusts and deep regional features, contributing to better understanding the complex subsurface geology of the Southern Apennines. Our advances interpretation strategy is able to efficiently revive deep legacy data like the CROP, which are unique and nowadays hardly to repeat. New important insights across seismically active areas worldwide can be obtained reproposing this workflow in other contexts, extending to depth the surface evidences of outcropping faults as well as revealing unknown structures to survey with targeted fieldwork mapping.