华南沿海地区海啸影响数值模拟与分析

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

应用海啸数值模拟模型(cornell multi-grid coupled Tsunami model,COMCOT)对华南沿海地区可能遭受的海啸进行模拟研究具有现实意义。基于COMCOT模型及马尼拉海沟潜在震源分段及其参数设置,模拟了不同震源引发多场海啸到达华南沿海地区的波高变化和到时特征。模拟分析发现,海啸到达中国福建省南部至广东省西部一带能够产生最大2.5m波高的海啸波,海南岛东部沿岸也会产生最大1.5~2.0m的海啸波,海啸传播到广西北部湾地区的最大波高在0.3 m以下;海啸波发生1.9h后最先到达海南岛东部沿岸,2.6h后到达香港、澳门及广东的汕尾一带地区,3.6h后到达福建南部一带及琼州海峡地区,8.9h以后到达北部湾地区。华南沿海不同地区海啸的首波波高和最大波波高对马尼拉海沟震源位置的敏感性存在差异性,其中广东沿海中段对马尼拉海沟震源位置最为敏感,震源断层2、断层3引发海啸在该地区的首波和最大波高接近2.5m,而震源断层1、断层6(断层编号依据2006年美国地质调查局资料)引发海啸在该地区的首波和最大波高只在1.0m上下。

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 hwhen the tsunami occurs,the lead wave firstly propagates to the eastern coast of Hainan Island.It costs 3.6 hto get to Qiongzhou Strait and the south of Fujian Province,and the maximum wave can reach 1.5-2.0 m.2.6 hlater,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 hlater,the wave travels to the Beibu Gulf,and the wave amplitude is less than30 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.