地震のダイナミクス. 誘導された地殻からの圧縮火山流体のマッピング 地震速度の低下
F Brenguier1, M Campillo2, T Takeda3
1Institut des Sciences de la Terre, Université Joseph Fourier, CNRS, F-38041 Grenoble, France. florent.brenguier@ujf-grenoble.fr.
まとめ
火山噴火は,深層流体の圧力から生じる. 科学者は,現在,これらの圧縮された火山地帯を,地震速度のストレス下での変化を測定することによってイメージすることができ,火山システムの特徴を明らかにしています.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- 火山学 火山学とは
- 地震学 地震学とは
背景:
- 火山噴火は,深い熱い火山流体からの圧力放出によって引き起こされます.
- 圧力流体の影響を受けた地域の範囲を理解することは,火山の危険性評価に不可欠です.
研究 の 目的:
- 圧縮された火山地帯のイメージングのための新しい方法を実証するために.
- 地震速度の変化と地殻のストレス乱れとの関係を調査する.
主な方法:
- 日本のハイネット地震ネットワークからの地震騒音記録を利用した.
- 2011年の東北大震災後の火山地帯における地殻の地震速度の変化を測定した.
- 動的ストレスによる機械的弱化の指標として地震速度の減少を解釈した.
主要な成果:
- 観測されたコセイズミック地殻の地震速度の減少は,火山地帯以下で顕著である.
- これらの減少を,地震波が誘発した動的ストレスによる圧迫地殻の機械的弱化と関連付けました.
- 地震速度の変化がストレス波動と相関することを実証した.
結論:
- 地震速度の動的ストレス干渉に対する感受性をマッピングすることは,火山系をイメージする新しい方法を提供します.
- この技術は,火山活動の特徴とモニタリングに役立ちます.
- 地下構造と火山の機械的状態についての洞察を提供します.
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