||The objectives of the GHASS (Gas Hydrates, fluid Activities and Sediment deformations in the western Black Sea) cruise are twofold but interconnected. The first aim is to study the dynamics of gas hydrates and free gas associated with geological and climate processes. The second aim is to identify the factors at the origin of observed sediment deformations and submarine landslides in two areas in the Romanian sector of the Black Sea. For the cruise we use quantitative approaches based on multidisciplinary studies (geochemistry, geology, geophysics and geotechnics). Gas hydrates and free gas were detected using surface and deep-towed HR seismic (SYSIF) techniques and by performing in situ geotechnical and acoustic measurements using the Ifremer penetrometer (Penfeld). Dynamics of gas hydrate and free gas were evaluated based on geochemical analysis of pore fluids but also by carrying out in situ geotechnical measurements and long-term monitoring (several years) of few key sites with pore pressure and temperature measurements. The deformation and submarine landslides associated with gas hydrates, free gas and/or the Danube canyon activities were also studied by using advanced geotechnical technologies and detailed sedimentological studies on sediment cores. One of the main results of the GHASS cruise was to recover gas hydrates from coring for the first time in the Romanian sector of the Black Sea.