地球の内核のゆっくりとした微分回転は,散乱の時間的な変化によって示されています
1Department of Earth and Space Sciences, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles 90095, USA. vidale@ucla.edu
Nature
|June 6, 2000
まとめ
地球の内核の自転は微妙ですが,検出可能です. 新しい地震データは,年0.15度の異なる回転速度を示唆し,以前の制約と整合し,地力学への洞察を提供している.
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
- 地球科学 地球科学 地球科学
背景:
- マントルに対する地球の内核の回転は,地力学と地力学学に重大な影響を及ぼします.
- 以前の研究では,差分回転が示唆されていたが,地震データ制限と潜在的なバイアスのために課題に直面した.
研究 の 目的:
- 散らばった地震波を用いて内核の動きを調査する.
- 内核の微分回転のより直接的なテストを提供するために.
主な方法:
- 地球の内核に散らばった地震波の分析.
- 米国モンタナ州で記録された,ノヴァヤ・ゼムリアの2つの核実験 (1971年と1974年) の分散波データの比較.
主要な成果:
- 地震波の散乱の小さな,一貫した変化が観察されました.
- 内核の微分回転速度が年間0.15度であることを示した.
結論:
- この発見は,内核の微分回転の存在を裏付けている.
- 推定された回転速度は,自由振動データからの制約と一致し,以前の不確実性を解消しています.
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