In polar regions, due to low temperatures, the upper limit of the hydrate stability zone occurs at a depth of approximately 150 meters.1[citation needed] The maximal depth of the hydrate stability zone is limited by the geothermal gradient.
Along continental margins the average thickness of the HSZ is about 500 m.[3] The upper limit in oceanic sediments occurs when bottom water temperatures are at or near 0 °C, and at a water depth of approximately 300 meters.1[citation needed] The lower limit of the HSZ is bounded by the geothermal gradient.
Conversely, the thickest hydrate layers and widest HSZ are observed in areas of low geothermal heat flow.
If this pressure is substantially changed, the stability of the methane layer above will be altered and may result in significant destabilization and disassociation of the hydrate deposit.
[5] Changing atmospheric and oceanic temperatures may impact the presence and depth of the hydrate stability zone, however, is still uncertain to what extent.