Probabilistic tsunami hazard analysis-application to Maanshan nuclear power plant in Taiwan

In the past twelve years, two earthquakes of magnitude 9.0 have occurred in the western Pacific. These earthquakes resulted in tsunamis, causing tremendous casualties, such as the nuclear disaster in Japan on March, 2011. Taiwan is an island located in the circum-Pacific belt, along which approximately 90% of the world's largest earthquakes take place. To prevent hazards, probabilistic tsunami hazard analysis (PTHA) is applied to nuclear power plants in the coastal regions of Taiwan. The approach developed here allows for the selection of reasonable tsunamis generated from distant earthquakes in the Manila Trench. Two types of uncertainty are considered: aleatory uncertainty and epistemic uncertainty. Concerning the aleatory uncertainty of modeling, a validation of prediction results is conducted against observed data. And a logic tree is introduced to help with epistemic uncertainty and set up different series of source parameters. In addition, a numerical model is used to simulate tsunami propagation and wave height. Under the assumptions of the logic tree and numerical modeling, the relationship between annual probability and maximum tsunami wave height can be obtained. Finally, tsunami hazard maps can be produced and the safety assessment of nuclear power plants can be carried out. The results provide useful information for engineering design and hazard prevention.