Study on amplification mechanisms of coastal hazard due to tsunami or storm surge combined with high-frequency wave components

2018 Fiscal Year Final Research Report

• Project/Area Number: 15H04046
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Hydraulic engineering
• Research Institution: The University of Tokyo
• Principal Investigator: Tajima Yoshimitsu 東京大学, 大学院工学系研究科(工学部), 教授 (20420242)
• Co-Investigator(Kenkyū-buntansha): 下園 武範 東京大学, 大学院工学系研究科(工学部), 准教授 (70452042) ; 佐藤 愼司 東京大学, 大学院工学系研究科(工学部), 教授 (90170753)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 高波 / 高潮 / 浸水 / 越波 / 波浪の重合 / 沿岸ハザード

Outline of Final Research Achievements

Video footage of recent severe coastal inundation events due to tsunami, storm surge and stormy waves indicates that combination of waves with different frequencies has significant influence on amplification of coastal inundation. This study first developed a facility, which can generate waves with different frequencies including a bore to represent such wave-wave and wave-surge interactions. The numerical models were then developed for computation of such non-linear dispersive tsunami propagation with soliton fission and interaction of breaking and broken storm waves with storm surge induced by winds and waves. The models were validated through application to various experimental and field cases and it was confirmed that the model reasonably capture the observed amplification of inundation due to wave-wave and wave-surge interactions. The models and experimental facilities are readily applied for estimation of coastal hazard for designs of disaster mitigation.

Free Research Field

海岸工学

Academic Significance and Societal Importance of the Research Achievements

現在の沿岸域におけるハザード推定には十分に考慮されていなかった高周波の波動成分と、津波や高潮、長周期波などの長周期成分との相互干渉による浸水ハザードの増大特性を把握するための実験装置と、そのような現象を物理的なメカニズムに即して再現可能なハイブリッド数値モデルが構築された。これにより、各地で異なる地形による影響や不規則波の不確実性に伴う影響も考慮したよりハザード推定の高精度予測が可能となる。