大規模な潜水地震の前に数千キロメートル規模の揺れ
Jonathan R Bedford1, Marcos Moreno2, Zhiguo Deng3
1Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, Germany. jbed@gfz-potsdam.de.
Nature
|May 1, 2020
まとめ
2010年のマウレ地震と2011年の東北大震災のような大規模な地震は,数ヶ月に及ぶ大規模な地表移動の逆転が先行した. これらの発見は,迫り来る巨大地震を予測する上で,より深い潜水過程の重要性を強調しています.
科学分野:
- 地理学
- 構造学
- 地震学
背景:
- 巨大地震は大きな自然災害のリスクを 引き起こします
- サブドクションゾーンは地球物理学的機器,グローバルナビゲーション・サテライト・システム (GNSS) を使って監視されています.
- 地震のメカニズムを理解するために 重要なGNSSデータです
研究 の 目的:
- 大規模な地震が起こる前に 表面の移転パターンを分析する
- 地震発生におけるより深い沈下ダイナミクスの役割を調査する.
主な方法:
- GNSSのタイムシリーズから地質学的な動きを分離するために,新しい軌道モデリングアプローチを使用した.
- 2010年のマウレ地震と2011年の東北大震災による地表移動データを分析した.
主要な成果:
- マウレ地震と東北大震災に先立つ4~8mmの地表移動の逆転が確認された.
- この逆転は数ヶ月 何千キロも続いたのです
- モデル化されたトーホク・オキ前移転は,スロースライドに続く急速なスラブ・プルダウンと粘着弾性反発を示唆しています.
結論:
- 予備地表の移動の逆転は,迫り来る巨大地震の重要な指標です.
- 地震のダイナミクスを大きく影響するメタステーブルスラブの密集化のような,より深い潜水プロセスです.
- 大きな地震を予測するには,プレート界面の摩擦とより深いダイナミック境界条件の両方を考慮する必要があります.
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