High-resolution seismic imaging in complex environments: A comparison among common-reflection-surface stack, common-midpoint stack, and prestack depth migration at the Ilva-Bagnoli brownfield site, Campi Flegrei, Italy

Abstract

I used the common-reflection-surface (CRS) stack technique together with conventional common-midpoint processing and prestack depth migration (PSDM) to process three parallel high-resolution seismic reflection lines acquired in a closed industrial plant. This brownfield site, now undergoing remediation, is located within the Bagnoli district of the city of Naples, Italy, near the southeastern border of Campi Flegrei caldera. Compared with the other results, the CRS stack, followed by poststack depth migration, produced a seismic image more consistent with the expected subsurface structures and with outcropping units present in the area. The survey confirmed the presence under the brownfield site of some buried steps of Coroglio Fault, a main structure formed approximately [Formula: see text] ago, during the Neapolitan Yellow Tuff supereruption. Results have important implications for hazard assessment and geothermal exploration because the imaged faults certainly are preferential passageways for geothermal fluids and washed pollutants. These tests revealed that the common-reflection-surface stack can be a fast and cost-effective alternative to PSDM in settings in which structural complexity and high levels of ambient noise make it challenging to obtain a reliable background velocity model; therefore, allowing high-resolution reflection seismology to be successfully used in those environments.