現代のニューマドリッド地震地帯における断層滑り率
1Department of Geological Sciences, University of Colorado, Boulder, CO 80309-0399, USA. Department of Geology, University of Arkansas, Fayetteville, AR 72701, USA. William Lettis and Associates, 1777 Botelho Drive, Suite 262, Walnut Creek, CA 945.
まとめ
後期ホロセンの沈殿物は,ニューマドリッドの地震地帯にあるリールフット推力断層の上の断層に関連する折り畳みを明らかにしています. この研究は,この地域の地震の危険性を理解するために不可欠な滑り率を定量化しています.
科学分野:
- 地質学 地質学 地質学
- 地震学 地震学とは
- 地質物理学 地質物理学とは地質物理学です.
背景:
- ニューマドリッド地震帯は,米国中部に位置する地震リスクの高い地域です.
- 盲断層の活動を理解することは,地震リスクの評価に不可欠です.
研究 の 目的:
- レイク郡地域における Holocene 後期の堆積物を分析し,Reelfoot 推力断層の上の変形を理解するために.
- リールフット推力断層とニューマドリッド地震地帯の滑り率を定量化するために.
主な方法:
- ホロセンの後半期の堆積物の構造と地形分析.
- リールフット・スカープをフォルト・ベンドの折りたたみ上の前肢として,溝の露出からのキック・バンド幅を用いてモデル化.
- 構造的なリリーフと推定された断層の沈みを使用して滑り落ち率を計算します.
主要な成果:
- 堆積物は,盲目のリールフット推力断層の上の断層に関連する折り畳みによって変形します.
- ブラインド・スラストの滑り率は,過去2300年 (+/- 100年) の 6.1 +/- 0.7 mm/年と推定されています.
- ブラインドスルースの代替滑り率の計算は,4.8 +/- 0.2 mm/年でした.
- ニューマドリッド地震地帯の右側滑り率は,年間1.8~2.0mmと推定されています.
結論:
- Reelfoot推力断層は活発であり,ニューマドリードの地震地帯の変形に寄与しています.
- スリップレートのデータは,地域の地震の可能性に関する重要な洞察を提供します.
- 幾何学的な関係から,右側滑りによる地震地帯全体の活動に対する特定の貢献が示唆される.
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