Numerical Simulation and Analysis of Tsunami Impacts on the Coastal Area of South China

The coastal area of South China overlooks the Manila trench across the South China Sea. Once a tsunami triggered by the earthquake in the trench that has frequent seismic activity, the tsunami energy may spread northward to the coast of China and influence the region. Based on the focal parameters of Manila trench which is divided into six segments, COMCOT (cornell multi-grid coupled tsunami model) is adopted to simulate six potential tsunamis. The six earthquakes are close to Mw9.0, and the epicenter of them distributes from north to south across the trench. By analyzing the height and arrival time of tsunami wave which propagates to the coastal area of South China, the results indicate that, after 1.9 h when the tsunami occurs, the lead wave firstly propagates to the eastern coast of Hainan Island. It costs 3.6 h to get to Qiongzhou Strait and the south of Fujian Province, and the maximum wave can reach 1.5-2.0 m. 2.6 h later, the region of Hong Kong, Macao and Swabue of Guangdong Province can detect the lead waves, and the maximum wave in this region is about 2.5 m. 8.9 h later, the wave travels to the Beibu Gulf, and the wave amplitude is less than 30 cm. The sensitivity analysis shows that the sensitivity to source location is different in different coastal regions of the South China. In general, the most sensitive area is the region of Hong Kong, Macao and most parts of Guangdong Province. If the tsunami is triggered by Fault2 and Fault3, the maximum wave height is near 2.5 m. However, in the case of Fault1 and Fault6, the maximum wave height is about 1 m.