プレイストセンの後半の侵食によるニューマドリッドの地震性の引き起こすこと
E Calais1, A M Freed, R Van Arsdale
1Purdue University, Department of Earth and Atmospheric Sciences, West Lafayette, Indiana 47907, USA. ecalais@purdue.edu
Nature
|July 31, 2010
まとめ
ミシシッピ湾の気候による侵食は,大陸中部の地震に影響を与えた. 川の切断からの下荷は地殻のストレスを軽減し,故障に近い断層を明らかにし,ニューマドリッドの地震地帯に大規模な地震を集中させました.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- テクトニクス (地質学) とは
- 四季地質学 四季地質学
背景:
- 地震の行動は,大陸板の内部と板の境界の間に異なっています.
- 中央大陸断層の活性化と地震活動の持続時間は十分に理解されていません.
- ニューマドリードの地震地帯は,最後の氷河期以来,集中した大規模な地震を経験してきました.
研究 の 目的:
- ニューマドリードの地震地帯で集中して発生する大規模な地震の原因を調査する.
- 中央大陸の地震性を気候制御された侵食史と結びつけるために.
- 断層の活性化と地震活動の持続を制御する要因を理解する.
主な方法:
- ミシシッピ州北部の水槽の侵食の歴史の分析.
- 堆積物下荷による石層屈曲のモデリング.
- 上層地殻のストレス変化と断層の振る舞いのシミュレーション.
主要な成果:
- ミシシッピ海域の気候制御による最近の侵食は,地震の集中と関連しています.
- 河川の切断 (16,000〜10,000年前) から生じた石層の屈折は,上層地殻の正常なストレスを軽減しました.
- このストレス削減により,既存の故障が明らかにされ,故障均衡に近い状態になりました.
結論:
- ミシシッピ川の浸食の歴史は,ニューマドリッドの地震性における重要な要因である.
- 失敗均衡に近い断層は,破裂に敏感である.
- 荷下ろしや過去の地震によるストレスの変化は,近い,破壊されていないセグメントの将来の破裂を引き起こす可能性があります.
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