広範囲にわたる地震波の反射性と,トンガマントルのメタソマチズムのケイジ
Yingcai Zheng1, Thorne Lay, Megan P Flanagan
1Department of Earth and Planetary Sciences, University of California, Santa Cruz, CA 95064, USA.
まとめ
地震画像は,トンガの沈殿地帯の上の深いマントルの構造を明らかにしています. これらの構造は,上昇する流体によって引き起こされ,地球を理解するための鍵です.
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
- テクトニクス (地質学) とは
背景:
- サブドクションゾーンは,地球の地殻の進化と石層のリサイクルに不可欠です.
- 潜水板の上の上層マントルのの動態を理解することは不可欠です.
- 地震画像は,これらの複雑な地質学的プロセスに関する洞察を提供します.
研究 の 目的:
- トンガ・スラブの上の上部マントルのの3D地震画像を作成するために.
- この領域内の反射界面を特定し,特徴づけること.
- 地震構造をマントル過程の観点から解釈する.
主な方法:
- P波とS波の反射のテレシーミック記録の移動.
- 沈下する海洋板からの下側の反射の分析.
- 上層マントルの3次元地震画像.
主要な成果:
- 様々な深さ (90~450km) で横断的に連続した弱反射器の検出.
- 重要な地形を持つ反射器の識別.
- 特定の深さでP波とS波の阻力量の減少が観察され,構成の変化を示しています.
結論:
- 普遍的な地震反射性は,相変化とメタソマチズムに起因する.
- マントルのを通って上昇するスラブ系流体は,これらの観測された構造を引き起こします.
- これらの発見は,潜水地帯のプロセスと大陸の地殻の生成に関する私たちの理解を高めます.
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