低コセイズミック摩擦は,温度測定から決定された東北沖断層のコセイズミック摩擦です

P M Fulton¹, E E Brodsky, Y Kano

¹Department of Earth and Planetary Sciences, University of California, Santa Cruz, CA, USA.

Science (New York, N.Y.)

|December 7, 2013

まとめ

研究者は,掘削孔の温度観測所を使用して,東北大震災後の断層摩擦を測定しました. この研究では,表面摩擦係数が低いことが判明し,地震動力学と断層の振る舞いに関する新しい洞察を提供しました.

科学分野:

地質物理学地質物理学とは地質物理学です.
地震学地震学とは
プレート・テクトニクス (プレート・テクトニクス)

背景:

断層摩擦は地震のダイナミクスとエネルギー消耗に大きな影響を与えます.
地震後の断層温度を測定することで,摩擦過程の洞察が得られます.
2011年の東北大震災は,日本溝のプレート境界に重大な滑り込みを引き起こした.

研究の目的:

東北大震災時の断層の摩擦抵抗を定量化するために.
散らばったエネルギーと故障温度との関係を調査する.
プレート境界の表面摩擦係数を測定する.

主な方法:

日本溝断層を横断する掘削孔温度観測所の設置.
地震後の9ヶ月間,温度異常をモニタリングする.
散らばったエネルギーと表面摩擦を計算するために,温度データを分析する.

主要な成果:

プレート境界断層で0.31°Cの温度異常が検出されました.
この異常は,地震中に散らばったエネルギーの27MJ/m2に相当します.
計算した表面摩擦係数は0.08でした.

結論:

東北大震災時の表面摩擦係数は,岩石の典型的な静的摩擦値より大幅に低かった.
この発見は,地震のエネルギー放出と断層滑行行動を理解するための意味を持つ.
掘削孔の温度測定は,地震の摩擦を推定するための貴重な方法を提供します.

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