Geohazards types and their distribution characteristics in the natural gas hydrate area on the northern slope of the South China Sea

Integrated investigation has revealed that the northern slope of the South China Sea (SCS) is a favorable place for gas hydrate accumulation and hence has stored a large amount of hydrate resources. Natural gas hydrates are mostly developed in areas of complex tectonic activity which are also areas of high-risk geological disasters. Potential hazard geological factors constitute great threats to the storage and commercial exploitation of gas hydrate. Based on a large number of 2D, 3D seismic profiles and multi-beam data acquired by the Guangzhou Marine Geological Survey over the years in the gas hydrate development zone in the northern part of the South China Sea, the authors conducted the seabed disaster geological study on the northern slope of the South China Sea. In this paper, the geomorphological features, the types, characteristics, genesis and distribution characteristics of the geohazards related to gas hydrate in the study area were comprehensively analyzed. The relationship between the geohazards and hydrate formation and decomposition was also discussed. The results of the study were used to predict the mineralization of gas hydrates on the northern slope of the South China Sea, thus providing a data basis for future disaster risk assessment and decisionmaking.