Évaluation de la morphodynamique sous-marine en Mer du Nord méridionale au cours de la période 1985-1995 / Evaluation of sea-floor sediment dynamics in the Flemish Banks (southern North Sea) between 1985 and 1995

Abstract

Abstract The aim of the paper is to evaluate and map changes in sea-floor elevation in a marine sandy epeiric environment as a tool in research on present-day sea floor sediment dynamics, especially of bank summits and swale floors, and to assess the mobility of banks and sand waves from sounding and hydrographie maps and from hypsometric profiles provided by sequential bathymétrie campaigns along fixed tracks. It provides a review of data acquisition techniques and data processing methods. It focuses on stability maps and on morpho- metric methods, especially on trend maps of elevation change. Superposed profiles and serial profiles allow to study in more detail the displacement of banks, the progression or retreat of bank flanks, sand-wave mobility and other related topics. It shows that each method has its own specific application field but that all are complementary. The paper presents numerous examples of application of different methods to the Flemish Banks. It also mentions the potential of new technologies developed since the 1990s: multi-beam bathymetry, local relief mapping and the interpretation of satellite images. It discusses the specific support of side-scan sonar to bathymétrie profiling and to echogram interpretation.