Hydrate Stability Zone

The gas hydrate stability zone is the depth interval where pressure and temperature allow methane and water to form solid clathrate hydrate, ice-like cages that trap gas. It requires high pressure and low temperature, so on continental margins it begins a few hundred meters below the seafloor and extends down until rising geothermal temperature crosses the phase boundary, marking the base often seen as a bottom-simulating reflector in seismic data. On Arctic shelves underlain by subsea permafrost, the zone can reach near the seabed. Warming bottom water or falling pressure shrinks the zone, dissociating hydrate and releasing methane, a hazard for seabed stability and a feedback in the carbon cycle.