変換された地震波でハワイの羽根管をマッピングする
Nature
|July 6, 2000
まとめ
地震データは,ハワイの下の深いマントルの羽根を明らかにし,上部マントルの低シーア波速度と薄まった移行地帯が証明されています. これは,ハワイの羽根のより暑い,下層マントルの起源を示唆しています.
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
- マントルダイナミクス マントルダイナミクス
背景:
- ハワイ諸島は,マントルのホットスポットに移動する海洋石層から形成されたと考えられています.
- 地化学的および重力学的データは熱い羽根を示唆しているが,直接的な地震的証拠は欠けている.
研究 の 目的:
- ハワイのマントルプルームの直接的な地震的証拠を提供するために.
- ハワイの下の上層マントルの構造と熱的状態を調査する.
主な方法:
- 圧縮から切断 (P-to-S) の地震変換相の分析.
- ハワイ諸島の地震計局で地震データを記録する.
主要な成果:
- ハワイの下の130~140kmの深さから,非常に低いシャー波速度 (<4km/s) のゾーンを特定しました.
- ハワイの南南西にある上部マントルの移行地帯 (410~660km) の薄くなりが見られた.
- アステノスフィアの超高温は約300°C,ハワイの羽根の温度はアイスランドの羽根よりも約100°C高いと推定されている.
結論:
- 地震観測は,アステノスフィアとマントルの移行地帯にあるハワイの羽根管の存在を裏付けている.
- 移行地帯の有意な薄まりは,アイスランドの羽根に似た,ハワイの羽根の下層マントルの起源を示唆しています.
関連する概念動画
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A household microwave and lasers are examples of standing electromagnetic waves in a cavity. When two conducting metal plates are placed parallel at the nodal planes, it creates a cavity where standing waves are formed. The cavity between the two planes is analogous to a stretched string held at the points x = 0 and x = L. Here, the distance 'L' between the two planes must be an integer multiple of half of the wavelength. The wavelengths that satisfy this condition are given by:


