融解分離とストレイン分割:地震性アニソトロピーとマントルの流れへの影響
B K Holtzman1, D L Kohlstedt, M E Zimmerman
1Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455, USA. holtz007@umn.edu
Science (New York, N.Y.)
|August 30, 2003
まとめ
地球上部マントルの溶融の存在は,地震性アニソトロピーに影響します. 通常,流れに平行する地震速度の方向は,融解が弱気帯を形成する際に切断から90度方向づけることができ,マントルのダイナミクスを解釈する方法を変えます.
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
- 固体地球科学 固体地球科学
背景:
- 上層マントルのダイナミクスを理解するには,地震性アニソトロピーの解釈が必要です.
- 地震速度の方向は,地域マントルの流動に並行していると考えられています.
- オリビンのa軸の方向性は,地震速度の指針の鍵である.
研究 の 目的:
- 溶融の存在と分離が地震アニソトロピーに与える影響を調査する.
- 部分的に溶けた地域における地震速度の方向とマントルの流れの関係を再評価する.
主な方法:
- この研究は,理論的に,オリヴィンのa軸の整列に溶けが及ぼす影響を検証しています.
- それは分離された溶融ネットワークで3次元変形をモデル化します.
- 弱い領域と強い領域の間のストレスの分断を分析する.
主要な成果:
- 融解の存在は,オリヴィン (olivine) のa軸の整列を弱める.
- 分離された溶融は弱いシアゾーンを形成し,シア方向から90度A軸の調整を引き起こします.
- これは,部分的に溶けたマントルのストレイン分割を示しています.
結論:
- 流動方向を直接示す地震速度の方向の仮定は,部分的に溶けた領域で挑戦されています.
- 地震アニソトロピーの新しい解釈は,変形し,部分的に溶けた地球の領域のために提案されています.
- この発見は,上層マントルの流動力学に関する新しい洞察を提供します.
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