爆発的な火山活動中に発生する地震やマグマの揺れ動いたり
A Mark Jellinek1, David Bercovici
1Department of Earth and Ocean Sciences, The University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada. mjellinek@eos.ubc.ca
Nature
|February 26, 2011
まとめ
爆発的な噴火の重要な指標である火山の振動は,マグマ柱がガスに富んだ環の中で振動する新しいモデルによって説明されています. これは,異なる火山で世界中で観測された一貫した震動周波数を説明します.
科学分野:
- 地質物理学 地質物理学とは地質物理学です.
- 火山学 火山学とは
- 地震学 地震学とは
背景:
- 絶え間ない振動 (0.57 Hz) である火山の震動は,しばしば爆発的な噴火に先行し,ガス流と地形変形に関連しています.
- 既存のモデルは,導管構造とマグマ組成の変動にもかかわらず,様々な火山で観察された一貫した震動周波数を説明するために苦労しています.
研究 の 目的:
- 火山の震動周波数の普遍性を説明する新しいモデルを開発する.
- 火山の振動振動を駆動する物理的メカニズムを調査する.
主な方法:
- マグマがベジキュラー・アヌルス内の柱状のプラグとして上昇する現代的な見方を利用した.
- マグマ柱の振動 ("揺れ") を基にしたモデルを開発し,アンヌルスの"ガス・スプリング"力に逆らった.
主要な成果:
- マグマの揺らぐモデルでは,震動周波数が導管の幾何学と構造に対して比較的無感であると説明しています.
- このモデルは,噴火時の震動周波数と帯域幅の上昇を予測し,爆発性と相関しています.
結論:
- 環状のガス噴出力に対して揺れるマグマ柱は,世界中の火山の震動の一貫した狭帯域周波数に対する堅固な説明を提供します.
- このモデルは,震動の特徴を噴火の動態と爆発性に関連付けることで,噴火の予測に関する洞察を提供します.
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