GNGTS 2017 - 36° Convegno Nazionale

588 GNGTS 2017 S essione 3.1 development of an accretionary wedge and for the occurrence of large mass transport deposits. The associated geologic hazard is the generation of large tsunamis that can affect the Atlantic coasts of Spain, Morrocco and Portugal, as it happened in the past. The aim of this work is to understand the origin of these wedge – shaped chaotic bodies underlying the TagusAbyssal Plain on the Gorringe Seamount’s northern flank and to contribute to understand the interaction between sedimentation and tectonic activity in this environment, in order to better assess the tsunami hazard for the region. Data and methods. The present work was accomplished based on the combined analysis and interpretation of geophysical data such as high resolution multi-beam swath bathymetry and multi-channel seismic reflection profiles. The bathymetric data belong to the SWIMcompilation, the result of 19 surveys carried out under the European Science Foundation EuroMargin SWIM project (Zitellini et al. , 2009). The seismic reflection data belong to 6 different datasets: Arrifano (Sartori et al. , 1994), IAM (Banda et al. , 1995), BIGSET (Zitellini et al. , 2001), TGS (private company), VOLTAIRE (Zitellini et al. , 2002), SWIM (Martinez-Loriente et al. , 2008). Bathymetric data were used to characterize the main morphotectonic features and to create a geomorphological map of the region: the bathymetric analysis was carried out for all the area surrounding the Gorringe Seamount. In addition, several seismic sections from the cited databases were analyzed in order to recognize and correlate the seismic units and the structures underlying the seafloor, reviewing the general stratigraphy of this area, considering the published stratigraphic models available (Hayes et al. , 1972; Ryan et al. , 1973; Sartori Fig. 1 - Main morphotectonic features of the SW Iberian margin, home of the Africa – Eurasia plate boundary. GB – Gorringe Bank; NGA – North Gorringe Avalanche; in grey the GCAW – Gulf of Cadiz Accretionary Wedge; in white the SWIM dextral strike – slip faults; in black the NE – SW trending thrusts and backthrusts; in yellow the mass transport deposits recognizable.