ロングバレーのカルデラにおける地震に伴う膨張過程
1Berkeley Seismological Laboratory, University of California, Berkeley, CA 94720, USA. U.S. Geological Survey, Menlo Park, CA 94025, USA.
まとめ
ロングバレー・カルデラの異常な地震現象は,火山や熱水活動が地震を引き起こすことを示唆している. これらの地震は,非二重カップル (NDC) のメカニズムを示し,流体圧の変化が断層形成に影響することを示しています.
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
- 火山学 火山学とは
背景:
- ロングバレー・カルデラの地震は,地表の過程によって影響を受けることがあります.
- 地震メカニズムを理解することは,火山や熱水による危険を評価する上で極めて重要です.
研究 の 目的:
- 1997年にロングバレー・カルデラで発生した地震の地震源メカニズムを調査する.
- ノンダブルカップル (NDC) 機構が存在し,特定の地質学的プロセスを示すかどうかを判断する.
主な方法:
- ブロードバンド波形を用いた地域地震モメントテンソーの決定.
- 1997年11月の地震群からの地震データの分析.
主要な成果:
- 地震 (Mw 4.6-4.9) は,有意な体積成分 (非二重カップルモメントテンサー) を有する異常な地震放射線を示した.
- 観測されたコセイズミック膨張は,水熱またはマグマ的プロセスによる直接のトリガリングを示唆しています.
- 類似のNDCソリューションは,これらの異常なイベントの共通のソースプロセスを暗示します.
結論:
- 異常な地震現象は,高圧流体注入またはマグマティック加熱によるストレス変化によって引き起こされた可能性が高い.
- 水熱またはマグマ的プロセスは,ロングバレー・カルデラ地域における地震性を引き起こす上で直接的な役割を果たしています.
関連する概念動画
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