TY - JOUR T1 - Effect of gas hydrates melting on seafloor slope instability A1 - Sultan,Nabil A1 - Cochonat,Pierre A1 - Foucher,Jean-Paul A1 - Mienert,J AD - IFREMER Brest, Dept Geosci Marines, F-29280 Plouzane, France. AD - Univ Tromso, N-9001 Tromso, Norway. UR - https://archimer.ifremer.fr/doc/00000/699/ DO - 10.1016/j.margeo.2004.10.015 KW - Storegga KW - Slope failure KW - GLE KW - Finite difference KW - Methane hydrate N2 - We present a theoretical study of the thermodynamic chemical equilibrium of gas hydrate in soil by taking into account the influence of temperature, pressure, pore water chemistry, and the mean pore size distribution. The model uses a new formulation based on the enthalpy form of the law of conservation of energy. The developed model shows that due to a temperature and pressure increase, hydrates may dissociate at the top of the hydrate occurrence zone to ensure a chemical equilibrium with the surrounding bulk water. This original result confirms what has been already shown through experiments. The second part of the paper presents an application of the model through a back-analysis of the giant Storegga Slide on the Norwegian margin. Two of the most important changes during and since the last deglaciation (hydrostatic pressure due to the change of the sea level and the increase of the sea water temperature) were considered in the calculation. Simulation results show that melting of gas hydrate due to the change of the gas solubility can be at the origin of a retrogressive failure initiated at the lower part of the Storegga slope. Once again, the developed model leads to predictions, which are supported by laboratory experiment results, but contradictory to previous interpretations and beliefs considering that hydrate dissociation occurs only at the bottom of the gas hydrate stability zone. Y1 - 2004/12 PB - Elsevier JF - Marine Geology SN - 0025-3227 VL - 213 IS - 1-4 SP - 379 EP - 401 ID - 699 ER -