Structural Measures Against Tsunamis

Recognizes that structures such as dikes play a crucial role in preventing disasters by controlling tsunamis, floods, debris flows, landslides, and other natural phenomena, but structural measures alone cannot prevent all disasters, because they cannot mitigate damages of hazards exceeding the level the structures are designed to withstand. The Great East Japan Earthquake demonstrated the limitations of Japan’s existing disaster management systems, which relied too heavily on dikes and other structures. Multilayered approaches to disaster mitigation can minimize damage by including structural and nonstructural measures and ensuring the safe evacuation of residents. Recommendations for developing countries include (1) preparing for disasters by integrating structural and nonstructural measures; (2) providing technical and financial support for local governments; (3) considering designs and improvements to enhance the resilience of structures and prevent sudden and complete failure; (4) raising dike levels in a phased manner; and (5) assuring reliable operation of key facilities during emergencies.