1960年のチリ大地震の先駆者であった
Marco Cisternas1, Brian F Atwater, Fernando Torrejón
1Facultad de Agronomía, Pontificia Universidad Católica de Valparaíso, Casilla 4-D, Quillota, Chile. marco.cisternas@ucv.cl
Nature
|September 16, 2005
まとめ
前回の地震以来の時間は,次の地震を確実に予測することはできません.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- パレオシズモロジー (Paleoseismology) とは
- テクトニクス (地質学) とは
背景:
- 地震の間の間隔が長ければ,次回の滑り方が大きくなるという一般的な仮定は,異議を唱える.
- この予測は,ストライクスリップ断層の大きな地震や,1960年のチリ地震 (M9.5) に対して,成功していないことが証明されています.
研究 の 目的:
- ナスカ・プレートと南米・プレート境界における巨大な地震の再発間隔を調査する.
- 巨大な地震の大きさの予測者としての時間以来の最後のイベントの有効性をテストするために.
主な方法:
- 埋もれた土壌や砂の層を含む古地震記録の分析.
- 過去2千年におけるテクトニック沈没と津波の洪水事件の再構築.
主要な成果:
- 1960年のチリ地震は,以前に示唆されたように123年ではなく,約400年の間隔が続いた.
- 古代地震のデータは,巨大な地震の間の長い間隔 (数世紀) がこの断層の典型であることを示しています.
- 1737年と1837年の小規模な地震は,蓄積された構造的緊張を完全に解放しなかった可能性が高い.
結論:
- 前回の地震以降の時間は,巨大な地震の大きさを予測する信頼できない指標です.
- このプレート境界の巨大な地震は,何世紀にも及ぶ周期で繰り返されます.
- 過去の小さな地震は,将来の大きな破裂のストレスを大幅に軽減しないかもしれません.
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