Offshore seismic reflection data: an oceanographic perspective

Recent studies have demonstrated that offshore seismic reflection data can be used to detect boundaries in the water column. This novel approach, called "seismic oceanography", has produced clear pictures of water mass interfaces (i.e., thermoclines, internal waves, fronts, eddies) in different oceanic environments. As the study of ocean circulation requires an extensive spatial and temporal coverage of observations, the possibility of using seismic data available from industrial or academic investigations to support and enhance oceanographic surveys seems very challenging. Since the Southern Ocean represents a key study area for climate due to the deep water formation process which triggers the Global Thermohaline Circulation, we began to reprocess seismic lines recently acquired off Wilkes Land (east Antarctica) in the framework of the WEGA project, to investigate the presence of reflections in the seawater column. A first evaluation of the possibility of recognizing fine structures in the water column is positive: seismic lines acquired along the Wilkes Land continental margin show signals correlated with boundaries inferred by conventional oceanographic measurements.