1986年7月8日のマグニチュード5.9のパームスプリングス北部地震の地震磁気観測

M J Johnston, R J Mueller

Science (New York, N.Y.)

|September 4, 1987

まとめ

1986年のノース・パームスプリングス地震の後に地震磁気偏移が観測されました. これらの永久磁場の変化は,難解な地震磁気効果の最初の直接的な証拠を提供します.

科学分野:

地質物理学地質物理学とは地質物理学です.
地震学地震学とは
地磁気学とは地磁気学である.

背景:

サンアンドレアス断層は磁気計配列によって監視され,地震磁気効果を検出します.
地震磁気効果,または地震による磁場の変化は,長い間予期されてきましたが,めったに観測されていません.

研究の目的:

地震磁気偏移の最初の直接観測を報告する.
観測された地震磁気オフセットの特性を分析し,地震モデルと比較する.

主な方法:

サンアンドレアス断層に沿って動作する24個の陽子磁気計の微分的に接続された配列を利用した.
1986年のノース・パームスプリングス地震の前と後の磁場データを記録した.

主要な成果:

観測された地震磁気偏移は,それぞれ3kmと9kmの震源距離で1.2と0.3ナノテスラであった.
観測されたオフセットは,バンニング断層の右側20cmの破裂を含む地震磁気モデルと一致しています.
観測された磁気変化は恒常的で,20分以内に完了した.

結論:

この研究は,地震磁気効果の最初の直接的な証拠を提供します.
このデータは,地震による磁場変化の物理モデルを裏付けている.
観測された永久磁場の変化の説明は,電動力学的な効果ではありそうにない.

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