外部上昇における脆性-柔性損傷によるダイナミック・スラブ・セグメンテーション
T V Gerya1, D Bercovici2, T W Becker3,4,5
1Department of Earth Sciences, Swiss Federal Institute of Technology Zurich, Zurich, Switzerland. tgerya@ethz.ch.
Nature
|November 11, 2021
まとめ
溝で板が曲がると損傷があり,板が弱体化して分割されます. この現象は,地球の歴史における主要な沈殿現象を説明し,頻繁にスラブ断裂の出来事を示唆している.
科学分野:
- 地理学
- 構造学
- 地球科学
背景:
- サブダクションはプレート構造と地球の熱化学的進化の主要な原動力である.
- 潜水板は,外側の上昇と溝の曲がり際に正常な故障を経験します.
研究 の 目的:
- 屈折によるプレート損傷が潜水ダイナミクスに及ぼす影響を調査する.
- サブダクション中の粒子の損傷を含む,脆性と柔らかな変形の相互作用をモデル化します.
主な方法:
- 数値的な潜水モデリング
- 粒子の損傷を含む脆性や柔らかな変形の自己一貫した追跡.
- 板の弱体化とセグメンテーションの分析
主要な成果:
- 浸透性スラブの弱体化とセグメンテーションは,外側の上昇に結合した脆性および柔らかい損傷の局所化により発生します.
- このスラブダメージ現象は,強いプレート/弱いスラブ二分法,正常な断層発生,地震異常,そして溝の近くの粘度低下を説明する.
- 壊れやすい粘着性のある破片は,より高いマントルの温度で離れる傾向があります.
結論:
- 屈曲による板の損傷は,潜水地帯の特徴を制御する重要なプロセスです.
- この発見は,強いプレートと弱いプレート,断層,地震異常,粘度変動の観測を調和させています.
- 断続的な沈下は,これまで考えられていたよりも,地球の歴史を通してより一般的であったかもしれない.
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