地震アニソトロピーの推論によるマントルの中部変形
James Wookey1, J-Michael Kendall, Guilhem Barruol
1School of Earth Sciences, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK.
Nature
|February 15, 2002
まとめ
地震波の分裂は,660kmの不連続性に近い中層マントルのアニソトロピーを明らかにする. これは,上層と下層のマントルの間のマントルの流れを阻害する潜在的な境界層を示唆しています.
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
- 地球科学 地球科学 地球科学
背景:
- コンベクティブマントルのプロセスは結晶を並べ,方向的な地震波速度で検出可能な地震アニソトロピーを生み出します.
- アニゾトロピーは,流れの変化により,通常上層マントル (石層) と下層マントル (D"領域) で観察される.
- この660kmの不連続は,地球の上層と下層のマントルの境界線を表しています.
研究 の 目的:
- 中部マントルの地震性アニソトロピーを調査し,特に660kmの不連続性について調査する.
- マントルの流れに影響を与える潜在的中部マントルの境界層の証拠を提示する.
主な方法:
- オーストラリアの地震測定ステーションからのシェア波分裂測定を用いて.
- トンガ・ケルマデックとニューヘブリッドの潜水地帯で発生した深い焦点の地震による地震波の分析.
主要な成果:
- これまでに報告された最も大きなシェア波分裂値のいくつかを観測した.
- 660kmの不連続の周辺で,有意な中部マントルのアニソトロピーが検出されました.
結論:
- 証拠は,少なくとも局所的に,マントルの中間境界層の存在を示唆しています.
- この境界層は,この地域の上層と下層のマントルの間の物質の流れを阻害する可能性があります.
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