| 研究課題/領域番号 |
23KF0149
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| 研究種目 |
特別研究員奨励費
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| 配分区分 | 基金 |
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| 応募区分 | 外国 |
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| 審査区分 |
小区分25030:防災工学関連
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| 研究機関 | 京都大学 |
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研究代表者 |
浅野 公之 京都大学, 防災研究所, 准教授 (80452324)
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| 研究分担者 |
HALLO MIROSLAV 京都大学, 防災研究所, 外国人特別研究員
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| 研究期間 (年度) |
2023-09-27 – 2026-03-31
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| 研究課題ステータス |
交付 (2023年度)
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| 配分額 *注記 |
1,900千円 (直接経費: 1,900千円)
2025年度: 500千円 (直接経費: 500千円)
2024年度: 1,100千円 (直接経費: 1,100千円)
2023年度: 300千円 (直接経費: 300千円)
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| キーワード | earthquakes / strong ground motion / site effects / amplification / spectral ratio / Kansai |
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| 研究開始時の研究の概要 |
ローカルな地震動の革新的予測手法の開発や地盤増幅率マップを構築するための手法開発と実際の地震観測記録等への適用を目的とした研究であり、本研究では関西地域を主たる研究対象地域とする。地震波動伝播の物理に基づく理論的な地盤増幅率モデル化手法の研究、実際の強震観測記録に基づく経験的地盤増幅率の抽出の研究を並行して行う。後者は前者の手法による結果の検証にも必要となるものである。理論的手法に基づく２次元地盤増幅率マップの作成にあたっては感度解析などによる検証も行う。
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| 研究実績の概要 |
In accordance with the Research Plan, we reviewed earthquake data and seismic velocity models available for the inner Kansai area (Osaka, Kyoto, and Nara basins). To investigate the empirical site response, we evaluated Horizontal-to-Vertical spectral ratios from 107,679 earthquake waveforms recorded in the years 1994-2023 at 449 monitoring sites (national, prefectural, and institutional monitoring networks). The processing was performed by our newly programmed software package that is custom-made for Japanese strong-motion waveform data. We found that the Fourier frequency and directionality of spectral peaks correlate with the thickness and disposition of the sedimentary lithological layer, respectively. These results were recently presented at the Annual Meeting of the Disaster Prevention Research Institute. Next, the physics-based site response modeling method is tackled in our newly published peer-reviewed publication. This method uses near-surface velocity profiles to predict the local amplification of seismic waves and it will be further developed in the next phase of this project. In addition, beyond the initial plan, we started with an analysis of the empirical site response at the strong-shaking zone of the M7.6 Noto earthquake, which occurred on January 1, 2024. This analysis is of interest because it is closely related to the project topic and up to date.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
1: 当初の計画以上に進展している
理由
Overall, the progress of this research project is smooth and without delays. In this phase, we investigated the empirical site response more deeply than originally planned, because of the occurrence of unexpected phenomena such as the directionality of spectral peaks. Still, it is in accord with the initial research plan. In the next project phases, we will focus on the spectral inversion of empirical amplification and further developments in the theoretical method. Beyond the initial plan, we started with an analysis of the newly emerged 2024 M7.6 Noto earthquake in order to study the site-specific response during strong ground shaking. This topic is important for the seismic hazard at long return periods, which are used for buildings of special importance (included in the initial research plan). We were able to perform the analysis very quickly because we utilized our new software package developed for the analysis of Japanese strong-motion data.
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| 今後の研究の推進方策 |
In the next phase of the project, we will finalize the analysis and proceed to publication about the site response during the 2024 M7.6 Noto earthquake. Then, following the initial Research Plan, we will evaluate the empirical amplification at selected sites in the Kansai area by using the spectral inversion method. The empirical amplification will be compared with a prediction by the theoretical physics-based method. Keeping in mind features investigated in the previous phase, we will perform developments in the physics-based method, and conduct sensitivity tests. Next, we will use the available Osaka-Kyoto-Nara basin velocity model and apply the method to produce regional 2D amplification maps. We will be able to submit a peer-reviewed paper in this project phase. Also, we plan to present our results at two national and one international scientific conference in FY 2024. There are no significant changes in the research plan, yet it is extended by the analysis of the 2024 Noto earthquake.
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