拡張によって引き起こされる米国西部の広範な深層地殻変形の地震的証拠
M P Moschetti1, M H Ritzwoller, F Lin
1Center for Imaging the Earth's Interior, Department of Physics, University of Colorado at Boulder, Campus Box 390, Boulder, Colorado 80309, USA. mmoschetti@usgs.gov
Nature
|April 9, 2010
まとめ
地殻における地震波の速度のアニソトロピーは,広範囲にわたる変形を明らかにする. この研究は,アメリカ西部の深層地殻の放射性アニソトロピーを,ケノゾイク期の広域構造プロセスと関連付けています.
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
- テクトニクス (地質学) とは
背景:
- 地球の物質における地震波の速度は,しばしばアニソトロピックである.
- 上層マントルのアニソトロピーは,変形と流れからのオリヴィン方向性に関連しています.
- 地殻の放射性アニソトロピーの観測は限られており,地殻の変形に関する理解を妨げています.
研究 の 目的:
- 大規模な地殻の放射性アニソトロピーを調査する.
- 地殻の変形と流れパターンを理解する.
- アニソトロピーをアメリカ西部の地質学プロセスと結びつける.
主な方法:
- アメリカ西部の環境騒音トモグラフィー.
- 地震波の速度変動の分析.
- アニソトロピーと地質学的な地域との相関関係.
主要な成果:
- 強い深層 (中から下) -地殻の放射性アニソトロピーが検出されました.
- アニソトロピーは,ケノゾイク期の広域地質学領域に限定されている.
- 偶然は,拡張的変形から鉱物の方向性を示唆しています.
結論:
- 米国西部の深層地殻の放射性アニソトロピーは,ケノゾイク期の拡張と関連しています.
- エクステンショナルの変形は,地殻のミネラルの格子型偏向を引き起こす可能性が高い.
- 伸縮と薄め時の深層地殻の広範囲で均等なストレスをサポートします.
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