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Updated: May 13, 2026

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Simulation of the Planetary Interior Differentiation Processes in the Laboratory
Published on: November 16, 2013
地震速度の半球的な変動は,地球の内核の上部にある
1Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington DC 20015, USA. niu@dtm.ciw.edu
Nature
|April 27, 2001
まとめ
地球における地震速度の変動.
科学分野:
- 地質物理学,地震学,地球科学 地球科学
背景:
- 地球の内核の地震速度の構造を理解することは,内核の成長プロセスを解明するために極めて重要です.
- 以前の地震研究は,主に100kmより深い構造を調査しており,内核の最上位100kmについては限られたデータしか得られていない.
研究 の 目的:
- 内核の境界直下の地震速度の変動を抑制するために.
- 最上部内核内の地震速度の地域差を調査する.
主な方法:
- 地震波が内核の境界に反射し,それを通過して伝達される間の移動時間差の分析.
- グローバル地震測定ステーションと地域地震ネットワークからのデータを活用した.
- 内核の異なる半球領域をサンプリングした波の移動時間残留を調査した.
主要な成果:
- 観測された系統的な移動時間残差は,内核の"西半球"と比較して"東半球"をサンプリングする波の場合は約0.8秒大きくなります.
- 残留値と波の横断角度との相関は見つかりませんでしたが,この地域での地震性アニソトロピーが最小であることを示唆しています.
- 東部内核のイソトロピック地震速度は西部内核の速度より約0.8%高いことが判定された.
結論:
- 地球の最上層の内核は,重要な地域的な速度異質性を表しています.
- 内核の東半球は,西半球よりも高い同極性地震速度を持っています.
- これらの発見は,内核の成長と構造を制御する物理的プロセスに関する新しい洞察を提供します.
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