波形トモグラフィーでは,海洋アステノスフィアの底辺で流れがチャネル化されていることが明らかになりました
Scott French1, Vedran Lekic, Barbara Romanowicz
1Berkeley Seismological Laboratory, Berkeley, CA 94720, USA.
Science (New York, N.Y.)
|September 7, 2013
まとめ
地質物理学者はプレート構造とホットスポット火山活動に影響を与える深層マントルの構造を発見しました. 準周期的,指のような低速度ゾーンは,地質プレートの下まで広がっており,深層マントルの物質の流入を示唆しています.
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
- プレート・テクトニクス (プレート・テクトニクス)
- マントラダイナミクス マントラダイナミクス
背景:
- マントルのコンベクションスケールとプレート運動やホットスポット火山活動のような地表地質現象の関係については,まだ十分に理解されていません.
- 既存のモデルは,深いマントルの過程と浅い板の動態を調和させるのに苦労しています.
研究 の 目的:
- プレート運動とホットスポット火山活動を駆動する深層マントルの構造を調査する.
- 浅層マントルと深層マントルダイナミクスの相互作用を理解するために.
主な方法:
- 完全波形地震トモグラフィーは,地球のマントルの内部でのシーア速度構造をイメージするために使用されました.
- 分析は,低速度ゾーンと,その空間的組織を様々な深さで特定することに焦点を当てました.
主要な成果:
- 低切断速度 (~2000 km 波長) の水平に伸びた準周期帯は,200〜350 km の深さでイメージされ,絶対的なプレート運動と並べられました.
- 400km以下では,下部マントルに根付いた,より少ない,波状,垂直的に一貫した低速の羽根が観測されました.
- これらの構造は,浅い低速地帯の下まで広がっています.
結論:
- この発見は,プレート駆動のマントルの流れと,マントルのより深い源から湧き上がる物質の間のダイナミックな相互作用を示唆している.
- 深いマントルの羽根は,動いている石層の下に水平に傾斜しているようで,表面地質に影響を与えています.
- これはプレート構造とホットスポット形成を駆動するメカニズムに関する新しい洞察を提供します.
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