核-マントルの境界にある可能性のある羽根の地震学的制約
Sebastian Rost1, Edward J Garnero, Quentin Williams
1Department of Geological Sciences, Arizona State University, Box 871404, Tempe , Arizona 85287-1404, USA. srost@asu.edu
Nature
|June 3, 2005
まとめ
地震波の分析により,オーストラリアの東にある地球のコアとマントルの境界にある,密度が高く,部分的に溶けたポケットが明らかになった. この複雑な構造は,純粋な溶融とは異なり,閉じ込められた結晶を示唆し,深い羽根の根帯を示している可能性があります.
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
- 地球科学 地球科学 地球科学
背景:
- 地球のコアとマントルの境界線は,単純なインターフェースではなく,複雑な構造を示しています.
- 地震波の速度減少は,最も下層のマントルの局所的な複雑性を示唆しています.
研究 の 目的:
- 核-マントルの境界にある特定の,密集した,部分的に溶けた物質のポケットの証拠を提示する.
- この異常の地震特性と影響を特徴づけるために.
主な方法:
- 異常な地震波 (ScP) の前駆者の配列分析.
- 圧縮波と剪定波の速度と密度の変化の計算.
主要な成果:
- オーストラリア東部で厚さ8.5km,幅50kmの密集した,部分的に溶けた物質のポケットを発見した.
- 観測された地震速度の減少 (8%の圧縮,25%のシア) と10%の密度の増加.
- 地震データは,溶融の非純粋な組成を示し,溶融を捕捉するメカニズムを必要とすることを示しています.
結論:
- 異常は,おそらく上部にある熱い領域から,閉じ込められた溶融によって形成された累積構造である.
- この構造は,上向きのマントル羽根の根帯を表しているかもしれない.
- この発見は,コア-マントルの境界の複雑な性質を強調しています.
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