上層マントルの流れの変化による西米山間地震性
Thorsten W Becker1, Anthony R Lowry2, Claudio Faccenna3
1Department of Earth Sciences, University of Southern California, Los Angeles, California 90089-0740, USA.
Nature
|August 28, 2015
まとめ
地殻の流れは重力エネルギーではなく プレート内の地震の主な原因です 改善されたモデルは 地震性をマントルの流れの変化に結びつけ 大陸の内部における地震の危険性に関する理解を深めています
科学分野:
- 固体地球地質学
- テクトノフィジック
- 地震学
背景:
- プレート内での地震は プレート構造理論に課題を投げかけます
- 米国西部の地震は"山間"帯に集中し,岩層構造の傾きと一致しています.
- これらのゾーンにおける地震性の局所化の正確な原因は十分に理解されていません.
研究 の 目的:
- マントルの流れの動態とプラーク内地震性の関係を調査する.
- プレート内での大陸変形と地震性の主要な要因を特定する.
- 構造的に活発な大陸地域における地震リスクの評価のための予測モデルを改善する.
主な方法:
- 地力学的プロセスをシミュレートするために改善されたマントルフローモデルを使用した.
- 地震率とダイナミック・トポグラフィの変化率 (マントルの流れによる垂直正規のストレス) の相関を分析した.
- マントルフローダイナミクスの予測スキルを他の潜在的なフォースリングと比較した.
主要な成果:
- 地震性とダイナミックな地形の変化の速度との間に重要な関係が特定されました.
- マントルの流れのダイナミクスは,他の調査されたフォースメントよりも高い予測能力を示した.
- 重力潜在エネルギーの変動は地震性においてマイナーな役割を果たしていることが判明した.
結論:
- 活発なマントルの流れは地震性プラーク内変形に大きく貢献する.
- 地震性の局所化は,岩層の強さの異質性によって調節される垂直正規のストレスにおけるコンベクティブの変化によって支配される.
- マントルの流れは,地形学,地質学,およびプレート内地域における地震の危険性に大きく影響する.
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