Gas hydrate accumulation at the Hakon Mosby Mud Volcano

Gas hydrate (GH) accumulation is characterized and modeled, for the Hakon Mosby mud volcano, ca. 1.5 km across, located on the Norway-Barents-Svalbard margin. Pore water chemical and isotopic results based on shallow sediment cores as well as geothermal and geomorphological data suggest that the GH accumulation is of a concentric pattern controlled by and formed essentially from the ascending mud volcano fluid. The gas hydrate content of sediment peaks at 25% by volume, averaging about 1.2% throughout the accumulation. The amount of hydrate methane is estimated at ca. 10(8) m(3) STP, which could account for about 1-10% of the gas that has escaped from the volcano since its origin.