Dissociation of gas hydrates by hydrocarbon migration and accumulation-derived slope failures: An example from the South China Sea

•Submarine slope failure by overpressure caused by gas migration/accumulation.•Buoyancy extrusion and seepage-derived deformation can generate slope failure.•Slope sediment permeability controls gas buoyancy and slope failures.•Slope failure results in the complete dissociation of the gas hydrate accumulation.