マントルの相変化と深層地震の断層は,地層を潜水する石層に発生します

S H Kirby, W B Durham, L A Stern

Science (New York, N.Y.)

|April 12, 1991

まとめ

350~690キロメートルの深さで発生する深い地震は,変形断層によって説明されます. このプロセスは,亜流層構造板内のオリビンに富んだペリドチットの相変化に関連したシール不安定性を含んでいます.

科学分野:

地質物理学地質物理学とは地質物理学です.
地震学地震学とは
ミネラル物理学ミネラル物理学

背景:

サブドクションゾーンには,傾斜した地震ゾーンがあり,明確な深層人口 (350~690km) がある.
伝統的な故障メカニズム (脆い破裂,摩擦スライディング) は,これらの極端な深さでは予想されません.
深い地震を理解するには,新しい地質物理学と地力学概念が必要です.

研究の目的:

350 km 以下の地震の発生と特性を説明する.
深層地震のメカニズムとしての変形断層の仮説を検証する.
深い地震分布とマントルの相変遷を相関させるため.

主な方法:

ミネラル・フェーズ・トランスフォーメーションに関する実験地質学のデータのレビューと合成.
ノンヒドロスタティック・ストレスの条件下でのシーア・インスタビリティの理論モデリング.
グローバル地震カタログと深層地震の地震データ分析.

主要な成果:

変形欠陥,つまり相変換中のシア不安定は,実行可能なメカニズムとして特定されています.
深い地震は,メタステーブルなオリビンに富んだペリドート岩ので発生すると仮定されています.
提案されたモデルは,観測された地球規模および地域規模の深い地震の分布と特徴と一致しています.

結論:

変換的断層は,潜水地帯の深い地震に対する一貫した説明を提供します.
メタステーブルオリビンの持続性は,地震が690kmまで発生することを説明しています.
マントルの相変化は,深い地震の発生と深さの限界において重要な役割を果たします.

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