[H-DS11] 津波とその予測

[HDS11-01] Predicting Tsunami Run-Up Characteristics through Comprehensive Computational Fluid Dynamics Analysis

*Peiwei Xie¹、Yan Du¹ (1.South China Sea Institute of Oceanology, Chinese Academy of Science)

キーワード：tsunami , numerical simulation , run-up height, run-up velocity , swash period

Accurate estimation of tsunami run-up is crucial for effective forecasting and early warning systems, yet developing a sufficiently reliable model remains a challenge. This study employs a self-manipulated Computational Fluid Dynamics (CFD) model to systematically simulate and analyze tsunami run-up characteristics. The simulations encompass a wide range of surf-similarity (0.9 to 11.9) and wave nonlinearity (0.1 to 8.9), leading to the formulation of novel run-up estimation methods. Our results reveal that, under fixed surf-similarity, tsunamis on mild slopes exhibit easier breaking, resulting in lower run-up heights compared to steep slopes. Waves with strong non-linearity experience more intense deformation and dynamics during their run-up than those with weaker non-linearity. We propose a semi-empirical method for conservative estimations of tsunami run-up height and velocity, relying on onsite wave measurements along the slope, thereby eliminating the need for arbitrary input from the beach's toe or offshore areas. Notably, this method demonstrates feasibility for waves with non-linearity up to 2.0, indicating its applicability across a broad spectrum of conditions. Additionally, we introduce an empirical formula for swash period estimation. Despite inherent limitations, the proposed method and formula present potential contributions to the toolkit for tsunami forecasts and early warnings, offering insights and alternative avenues for further exploration in this complex field.