Explanation:

They are found in continental shelves. Gas hydrate is a solid ice-like form of water that contains gas molecules in its molecular cavities1. In nature, this gas is mostly methane. Methane gas hydrate is stable at the seafloor at water depths beneath about 500 m. The gas hydrate stability zone extends into the seafloor sediments down to a depth where temperature exceeds gas hydrate stability, usually some 10s to 100s of meters beneath the seafloor. At this depth, thin methane gas layers are often present causing strong reflections in seismic records. The reflections approximately follow a line of constant temperature. Temperature in the subsurface is a function of heat flow and depth, so the reflections usually mimic the shape of the seafloor. Hence, they are named bottom simulating reflections (BSRs).