Experimental Model Of Pockmarks From Gas Hydrate Decomposition By Aeration

The decomposition of gas hydrates releases gas and water at volumes much larger than the original volume. The gas escapes violently, which destroys seabed sediments and can even cause geological disasters. To explore the effect of natural gas hydrate decomposition on underwater slopes, laboratory experiments were conducted to observe the features of slope failure. Aeration was used to model the gas that was produced by hydrate decomposition, and the results were as follows. (a) Once air filled into the bottom of the underwater slope, the pore pressure at the slope was altered, which eventually caused the slope to fail. (b) The formation of pockmarks corresponded to the variations in the pore-water pressure. (c) The theoretical analysis results showed that the sedimentation rate of fine particles (d < 0.4 mm) was lower than the water flow velocity, indicating that these particles were carried away with the air-liquid two-phase flow, which eventually caused the pockmarks to develop into craters.