遅い変形と低い地震の危険性は,新しいマドリッドの地震地帯にある
1Department of Geological Sciences, Northwestern University, Evanston, IL, 60208, USA. Department of Geology, Grand Valley State University, Allendale, MI 49401, USA. Department of Geological Sciences, University of Missouri, Columbia, MO.
Science (New York, N.Y.)
|April 24, 1999
まとめ
グローバル・ポジショニング・システム (GPS) のデータは,ニューマドリッド地震地帯 (NMSZ) の動きが最小であることを明らかにしています. これは,NMSZにおける大規模な地震による地震リスクが過大評価されている可能性を示唆し,以前の仮定に異議を唱える.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- 地震学 地震学とは
- プレート・テクトニクス (プレート・テクトニクス)
背景:
- 米国中部のニューマドリード地震地域 (NMSZ) は,歴史的に重要な地震活動がある地域です.
- 以前のNMSZにおける地震リスクの評価は,過去の大規模な地震に対して,しばしば高級度の地震を想定していた.
研究 の 目的:
- ニューマドリード地震地帯 (NMSZ) の地震リスクを再評価し,現在の地質データを分析する.
- 新しい証拠に基づいて,NMSZにおける大規模な地震の再発間隔を評価する.
主な方法:
- NMSZ全域の連続的なグローバルポジショニングシステム (GPS) 測定の分析.
- NMSZのGPSデータとプレート幅のGPSデータの比較.
- 周波数-大きさの関係が地震性データに適用される.
主要な成果:
- GPSの測定は,NMSZ内の地殻の動きがほとんどないか全くないことを示しています.
- これらの発見は,プレート幅のGPSデータと一致し,有意な動きを示していない.
- NMSZにおけるマグニチュード8の地震の暗示的な再発間隔は2500年を超えており,これはこれまで考えられていたよりも長い.
結論:
- NMSZにおける大きな地震によって引き起こされる地震の危険性は,過大評価されている可能性があります.
- NMSZにおける過去の大規模な地震は,一般に信じられているよりも小さかったかもしれません.
- 現在の地質学的データは,NMSZの高滑り率モデルをサポートしていません.
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