This study presents a new framework of simulation-based tsunami risk assessment with the help of a mode decomposition technique. In the proposed framework, a series of numerical simulations is performed in consideration of uncertainties to investigate tendency of a risk index. Spatial modes are then extracted from the simulated results using the theory of the proper orthogonal decomposition (POD), and a surrogate model is defined as a linear combination of the spatial modes. After the surrogate model is obtained, the Monte Carlo simulation is performed using the surrogate model to discuss tsunami risk based on probabilistic risk analysis. In this study, the proposed method is applied to risk evaluation of the tsunami force acting on the buildings in a simple condition. According to the obtained results, the proposed framework can provide an efficient approach of the probabilistic tsunami risk analysis, and it has high potential for disaster risk evaluation.
