The STOCKLINe 20 cruise, following STOCKLINe 19 (june 2019) is related to the problem of available sediments. More specifically, the objective of the two surveys is to quantify the volumes of sediments that are stored in the shoreface areas and that are potentially available for adjacent foreshore supply.

The quantification of available sediments is based on the identification of mobile sediments under the action of modal and exceptional hydrodynamic agents (tide, waves, waves), these sediments resting on an immobile substrate (rocky geological substratum, very coarse substrate) . This quantification is done mainly on the basis of HR to THR seismic data allowing to identify the cover of mobile sediments on an immobile substrate.

Many seismic missions have already been carried out along the Normandy coasts. The objective of the STOCKLINe surveys is not to prospect all the norman coastline. The goal here is to obtain seismic data on areas that have not yet been prospected or for which the seismic data already obtained do not allow evaluating the volumes of subtidal sandy stocks.

The first mission STOCKLINe 19 focused on targets between the Tréport and the Baie des Veys. The STOCKLINe 20 cruise allows to complete the surveys, mainly along the west coast of Cotentin.

STOCKLINe-2 is presented in the framework of regional research project "SELINe" (Sédiments des Littoraux de Normandie) funded by the Normandy region for a period of 36 months from October 2018. SELINe brings together all the Norman laboratories in geosciences (UMR M2C Universities of Caen and Rouen, UMR LETG-Geophen University of Caen, UMR LOMC University of Le Havre, Intechmer-Cherbourg).

Simultaneously to the seismic acquisitions (mini-sparker and / or bommer, brought by the applicant), we want to obtain a multibeam echosounder imaging (Thalia EM2040). Multibeam imagery will enable us to obtain data on sedimentary surface bedforms and, through this, on the modes of transport at the level of sandy stocks (direction, intensity) so as to better understand the importance of cross-shore and longshore fluxes. This work will be completed in certain sectors by sediment sampling to carry out geostatistical transport modeling.