International Journal of Ocean and Coastal Engineering

Potential tsunamis in the western Pacific Ocean pose great threats to the Chinese coastal areas. Among all possible tsunami source regions, the Manila subduction zone draws the most attention and there have been many research works on the tsunami hazards in the South China Sea. In this study, we evaluate the tsunami hazard along the Chinese coast by investigating more potential sources, including the subduction zones of Manila, Ryukyu, Nankai, Izu–Bonin and Mariana. Two tsunami scenarios are considered for each subduction zone, a worst scenario of earthquake magnitude 9.0 and a scenario of largest earthquake magnitude known in history in this zone. Earthquake source parameters are calculated using scaling relations that have been shown to be suitable for tsunami generation. Our results show that for the Chinese coast, tsunami hazards from the Manila and Ryukyu subduction zones are severe in the worst scenarios, and tsunami hazards from the Nankai, Izu–Bonin and Mariana subduction zones are mild. Using the largest earthquake magnitude in history, tsunami hazards from all the investigated subduction zones are almost negligible. Through a sensitivity test on earthquake magnitude, we find that earthquakes of magnitude of 8.5 or larger in the Manila and Ryukyu subduction zones cause severe tsunami hazard along the Chinese coast with wave amplitude over 2 m.

This study focuses on the application of structured cementing technology in the marine environment, which is based on self-compacting cement-based materials and underwater self-protecting casting cementing technology. In this study, cylindrical samples of structuralized cemented stone columns are developed in the laboratory to test material strength and other key features related to the material. Following this line, extensive numerical experiments are conducted to investigate the interaction between in situ sea mud and cemented stone column-seawall systems. The methods developed in this study will provide a technical basis for understanding the behavior of the newly invented cemented stone column-seawall system from a numerical perspective.