Historical evolution of the littoral prism of the Thau lagoon barrier (Sete, South-East France). Very high-resolution reflection seismic investigation.

Very high-resolution seismic data have been obtained recently, in the frame work of the research programme PNEC (French National Programme of Coastal E nvironment), on the shoreline area of Sete (Mediterranean coast, South East France). These data provide an accurate picture of the internal structure of the shoreline body. Seismic results combined with data about the morphos edimentary evolution of the study area, vibrocore data and results from arc haeological investigations yield clues to the historical evolution of the s tudy area. Especially, it is pointed out that the functioning of the presen t-day shoreline, by comparison with the system built in classical times, is characterized by a severe reduction in sediment supply and in volumes of s and involved in the shoreline dynamics. (C) 2000 Academie des sciences / Ed itions scientifiques et medicales Elsevier SAS.