Narrow Results

Taught by the lesson from the 2011 Tōhoku earthquake and tsunami, we aim to probe into the potential large-scale trench-typed tsunami threats to Taiwan by means of the deterministic method. In this paper, 18 trench-typed tsunami sources and the 4 fault-typed tsunami sources will be constructed. The detailed construction, including the rupture length and width, the scale of seismic moment, the slip as well as the dip angle, will be elaborated. The tsunami numerical model, COMCOT, will be applied to simulate tsunami propagation, run-up and inundation; multi-nested grids will be used for a complete simulation of the process of a tsunami from the beginning to the inundation. The simulation result shows that tsunami source from the northern segment of the Manila Trench will pose a serious threat to the safety of Taiwan's southwest coast. The tsunami energy from the Yap Trench can be substantially projected onto Taiwan, and threatens the coasts of northern, eastern, southern, as well as south-western Taiwan. The tsunami source from off the coast of Hualien will have a greater influence on the east coast of Taiwan.

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.