余震の密度が距離とともに減少することは,動的ストレスによる誘発を示さない
Keith Richards-Dinger1, Ross S Stein, Shinji Toda
1Department of Earth Sciences, University of California, Riverside, California 92521, USA. keithrd@ucr.edu
Nature
|October 1, 2010
まとめ
余震の静的およびダイナミックなストレス誘発について議論されています. この研究は,動的誘発を否定し,地震リスクの予測を再評価する必要があることを示しています. 余震距離の衰退は,ダイナミック・ストレスのみによるものではない.
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
- 地震科学 地震科学 地震科学
背景:
- 地震の相互作用を理解し,地震の危険を予測するには,余震の静的および動的ストレストリガーを区別する必要があります.
- 以前の研究では,動的誘発が,力法則の崩壊分析に基づいて,余震の距離の崩壊を説明することを示唆していた.
研究 の 目的:
- 地震余震距離衰退の代替説明を提案し,テストする.
- 動的ストレスが余震後の距離崩壊の唯一の要因であるという仮説を再評価する.
主な方法:
- 様々な距離のメインショックの前後における地震性崩壊パターンを分析する.
- 余震の時間的な崩壊 (オモリ法) を調べる.
- 余震のタイミングを地震波の到来と比較して調べる.
主要な成果:
- メインショックの5分前と5分後の地震性崩壊は300mを超えて区別がつかないため,動的なトリガー効果がないことを示しています.
- 余震の特徴であるオモリ側頭葉衰退は,メインストークから10km以上離れたところには存在しない.
- 観測された距離崩壊は地震波が到着する前に発生し,因果関係に違反し,ダイナミックトリガーに挑戦します.
結論:
- 余震の観測された距離の衰退は,ダイナミックトリガによってのみ説明されるわけではない.
- 余震の分布と触発メカニズムの代替説明が必要である.
- 断層破裂やスエームの連続的な誘発に関する仮定を再考することは,正確な地震リスク評価に不可欠です.
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