Types and Formation Mechanism of Typical Submarine Geological Hazards of Coastal Islands in China

Single beam, side-scan sonar, sub-bottom profiler and other survey equipments are adopted for investigation of submarine geological hazards in 15 coastal islands of China, namely, Zhangzi Is., Changxing Is., Caofeidian Is., Lingshan Is., Tuoji Is., Beichangshan Is., Chongming Is., Liuheng Is., Waidiaoshan Is., Xiushan Is., Zhujiajian Is., Jintang Is., Dongshan Is., Donghai Is. and Weizhou Is.. Data analysis and researches show that typical submarine geological hazards of coastal islands in china mainly cover 10 types: submarine landslide, submarine slope, seabed erosion, tidal ridges, moving sandwaves, shallow gas, wedge-shaped deposits, buried oblique layer, seabed siltation and coral reef degradation, and can be classified into gravity - hydrodynamic force cause, hydrodynamic force cause, pneumatic force cause, biological activity cause and human activity cause, among which hydrodynamic force cause accounts for the largest proportion and seabed erosion is the most developed, with the proportion of geological hazard attributed to human activity increasing rapidly.