琼东南外陆架灾害地质特征分布规律及成因分析OA北大核心

A variety of geological disaster features are developed at outer continental shelf of the Qiongdongnan Basin.Based on the shipborne survey data,AUV(Autonomous Underwater Vehicle)survey data,and 3D seismic data,this study precisely characterizes the geological disaster features within the water depth range of 100-250 m in the study area and analyzes their causes and controlling factors.After the analysis,the disasters in the study area are classified into two major categories,namely,submarine disaster factors and shallow geological disaster factors.Among them,submarine disaster factors include submarine bulges,submarine pockmarks,ancient coasts,subma-rine scarps,and sand waves,shallow geological disaster factors include active faults and shallow buried channels.The results of the analysis show that the geological disaster factors at outer continental shelf of the Qiongdongnan Basin are mainly controlled by sea level changes,tectonic activities,and sediment supply factors.Residual ancient coasts,sand waves,submarine scarps,and shallow buried channels are mostly related to sea level changes,whereas active faults,submarine bulges,and submarine pockmarks are mostly controlled by regional tectonic activities.Af-fected by the sediment supplies,the eastern part of the study area is more prone to develop coastal features domi-nated by carbonate coasts and carbonate platforms,whereas the western part is more likely to develop features re-lated to terrigenous sediments,such as sand waves and shallow buried channels.