| Project/Area Number |
20K22432
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| Research Category |
Grant-in-Aid for Research Activity Start-up
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| Allocation Type | Multi-year Fund |
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| Review Section |
0303:Civil engineering, social systems engineering, safety engineering, disaster prevention engineering, and related fields
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Project Period (FY) |
2020-09-11 – 2023-03-31
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| Project Status |
Completed (Fiscal Year 2022)
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| Budget Amount *help |
¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000)
Fiscal Year 2021: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
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| Keywords | 津波 / 周波数応答 / 応答関数 / 海溝型地震 / 津波応答関数 / 南海トラフ地震 / 津波増幅率 |
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| Outline of Research at the Start |
沖合で発生した津波は,地形の影響を受け沿岸で波高が増幅される.津波の増幅特性は水深比だけでなく水深方向の地形特性にも影響されるが,この地形効果は複雑であり定量化は行われていない.本研究では,津波モンテカルロシミュレーション結果から地形の周波数応答関数を推定し,沿岸域における津波の増幅率を定量化する.伝播経路上の津波波形のスペクトル変化を求め,多数シナリオのアンサンブルによって広い周波数領域での津波増幅成分を推定し,応答関数を求める.得られた応答関数は平均的な津波の増幅率となり,その空間分布や特徴について評価を行う.これらの成果は津波即時予測の精度改善に直結し,沿岸被害の低減を目指すものである.
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| Outline of Final Research Achievements |
Tsunami responses in frequency domain due to bathymetry effect were quantitatively obtained. First, tsunami simulations were performed for the Nankai Trough earthquakes using a stochastic fault generation model. From the tsunami simulation results, the tsunami response functions were obtained by performing a spectral analysis of the simulates tsunami waveforms in the source and coastal regions. The obtained response were validated by comparing them with the resonance periods estimated from the linear wave theory. As a result, the predominant periods corresponding to each scale in the tsunami propagation process was extracted by ensemble of spectral ratios among the scenarios. The extracted response functions are consistent with the theoretical resonance period under simplified topographic conditions, indicating the validity of the method.
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| Academic Significance and Societal Importance of the Research Achievements |
津波や高潮などの長波の挙動は海底地形の影響を大きく受ける．本研究では，地形によって津波がどのよに応答し，沿岸域でどのように増幅するかを定量化した．この応答は，外洋から沿岸部へ進行する津波の変化を予測しうるものであり，即時予測手法の改良や沿岸域での津波の継続時間の予測への応用が期待される．
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