地球の"ハム"は,大陸棚の上の海波によって引き起こされる

Spahr C Webb¹

¹Lamont Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA. scw@ldeo.columbia.edu

Nature

|February 16, 2007

まとめ

地球の地震のうなり声は,以前は大気の乱流に起因すると考えられていたが,主に大陸棚の海波の相互作用によって発生する. この発見は,大規模な地震がない場合に,連続的な地震エネルギーの源を明らかにします.

科学分野:

地質物理学地質物理学とは地質物理学です.
海洋学海洋学海洋学
地震学地震学とは

背景:

地球の地震の正常モードは,大きな地震が起こらない場合でも",ハム"として知られる恒常的な背景興奮レベルを示します.
この地震騒音の起源は議論されているが,大気の乱流が提案されているが,ますます疑問視されている源である.

研究の目的:

10mHz近くの周波数で地球の地震のブームを駆動する主要な源を調査する.
主要な興奮メカニズムとして,大気の乱れと海洋の源を区別する.

主な方法:

地震正常モードの興奮レベルを分析する.
海洋波と地震波の結合メカニズムをモデリングする.
地震データと海洋波データ,大気渦巻モデルとの比較.

主要な成果:

乱れは,地震の弱い源として特定されています.
浅い大陸棚の上での相互作用する海波が支配的な原動力であることが示されています.
海洋波と地震モードの間の計算されたカップリングメカニズムは,観測された地震スペクトルを正確に再現します.

結論:

大気上の乱れではなく,海の波が,地球の地震の主要な原動力である.
相互作用は,海洋表面における二次的非線形性によって起こり,海洋波と地震波を結びつける.
時間の相関は,海洋波の活動と地震モードの興奮の間の因果関係を確認しています.

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