Dynamic response of oceanic hydrates to sea level drop

Abstract

During sea-level drop, water and gas pressures within oceanic hydrate systems can exceed the total vertical stress and this can drive slope failure and gas venting. We investigate this behavior with a multi-phase fluid and heat flow model. During sea-level drop, fluid pressures drop much less than the total stress due to both the high gas compressibilitẏ and hydrate dissociation. In permeable sediments, hydrate dissociation, water expulsion and gas mobility combine to induce underpressure and downward water flow from the seafloor. This study provides a causal mechanism for slope failure and fluid exchange that occur in hydrate systems during sea-level fall. Copyright 2009 by the American Geophysical Union.