Effectiveness of Engineered Tsunami Mitigation Measures: A Review of Current Approaches and Research Needs, Part II: Experimental and Numerical Assessment

Laboratory experiments and numerical modeling are essential tools for understanding the performance of engineered tsunami mitigation measures, enabling controlled investigation of complex hydrodynamic processes that are difficult to capture in real events. This review critically evaluates current research on key structural countermeasures, seawalls, breakwaters, and water-filled canals, focusing on findings from physical modeling and computational simulations. Evidence from numerical and laboratory studies demonstrates that properly designed mitigation structures can reduce tsunami wave energy, delay inland inundation, and decrease forces on downstream infrastructure. The effectiveness of these measures is strongly influenced by structural geometry, placement, and maintenance, as well as by accurate representation of flow dynamics in experiments and simulations. Despite significant advances, important gaps remain, including the validation of numerical models against high-fidelity experiments, the assessment of extreme events, and the evaluation of hybrid or integrated strategies combining multiple mitigation measures. This review identifies these gaps and highlights research priorities aimed at improving predictive capabilities, optimizing structural designs, and supporting the development of reliable, scalable, and context-specific tsunami mitigation solutions.