Nouvelle modélisation des écoulements gravitaires sous-marins : application à l'effondrement de Nice de 1979

Abstract

We propose to apply in this note a simple mathematical model for the sedimentation of gravity deposits in deep water. An inverse method has been developed in order to characterize the parameters associated with the submarine flow. This method also provides the initial conditions, which constitute a major uncertainty in geoscience modelling. Application of the inverse method to the 1979 Nice airport collapse (southern France), constrained by cable breaks and/or deposit thicknesses, leads, for example, to the estimation of the initial volume and/or the physical parameters of the flow (friction coefficient, modified turbulent Schmidt number, etc.). The application of the model to this real case shows that only the simultaneous inversion of dynamic (cable break times) and sedimentological (deposit) data allows a satisfactory reconstruction of the flow.