アメリカ合衆国西部の下のアステノスフィアの密度,温度,弾性モジュールを探査した
1Seismological Laboratory, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA. takeo_ito@nagoya-u.jp
まとめ
海洋の潮が地球を明らかにする.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- 固体地球科学 固体地球科学
- 地震学 地震学とは
背景:
- 海洋の潮は地球表面に周期的な負荷を及ぼします.
- これらの潮負荷は,測定可能な表面の移動を引き起こします.
- これらの反応を理解することで,地球の内部についての洞察が得られます.
研究 の 目的:
- 地球の地殻と最上層マントルの構造をモデル化するために.
- 密度と弾性モジュールを独立に推定するために.
- アメリカ西部下のアステノスフィアを調査する.
主な方法:
- 表面の移転に関する地質観測を用いて.
- 海洋の潮負荷によって引き起こされる移動を分析する.
- 深度依存の地球物理モデルを開発する.
主要な成果:
- アステノスフィアの境界で,密度と弾性切断モジュールの強いグラデーションを特定した.
- 220kmの深さで構造的な断絶は認められませんでした.
- 低密度異常 (~50 kg/m3) をアステノスフィアに閉じ込めました.
結論:
- ~300°Cの温度異常は,アステノスフィアの低密度と弾性モジュールを説明する.
- 海洋の潮負荷は,地球の構造を調査するための有効な方法です.
- 米国西部の下のアステノスフィアは,著しい変動を示しています.
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