2004年パークフィールド地震中の高周波二次イベントである
Bettina P Allmann1, Peter M Shearer
1Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0225, USA. ballmann@ucsd.edu
まとめ
研究者らは,2004年のパークフィールド地震中に,高周波地震を特定した. この地震放射線の爆発は,急激な滑り方の成長を示唆し,地震の破裂のダイナミクスについての洞察を提供します.
科学分野:
- 地震学 地震学とは
- 地震科学 地震科学 地震科学
- 地質物理学 地質物理学とは地質物理学です.
背景:
- 2004年のパークフィールド地震 (マグニチュード6.0) は,地震の破裂プロセスを研究するための貴重な地震データを提供します.
- 地震放射線の空間的および時間的進化を理解することは,地震の危険性評価に不可欠です.
研究 の 目的:
- 2004年パークフィールド地震中の特定の高周波地震放射線イベントを特定し,特徴づけること.
- このイベント,滑り分布,および破裂速度との関係を調査するために.
主な方法:
- 2004年パークフィールド地震の地震記録を利用した.
- 震災をイメージするために3次元波形バックプロジェクション方法を採用しました.
- 異なる地震の到着を分析し,長期のスリップ逆転を行った.
主要な成果:
- 断裂開始から5秒後,低中心部から北西13キロメートルで,高周波地震放射線の爆発が確認されました.
- このイベントは,大きな滑り台の縁の近くに位置し,突然の滑り台の成長を示唆しています.
- 破裂速度を2.5km/sと推定し,地震破裂の北部の平均ストレスの低下が低いことを発見しました.
結論:
- 高頻度イベントは,パークフィールド地震中の局所的で突然の滑り加速を示しています.
- 結果は,余震によるストレス減少の推定値と一致し,破裂地帯全体でのストレス減少の変動を支えています.
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