2011年のマグニチュード9.0の東北大震災における共地震の上位プレート制御
Dan Bassett1, David T Sandwell1, Yuri Fialko1
1Scripps Institution of Oceanography, La Jolla, California 92093, USA.
Nature
|March 4, 2016
まとめ
2011年の東北大震災
科学分野:
- 地理学
- 地震学
- プレート構造
背景:
- 2011年の東北大震災 (Mw ≥9.0) は前例のない地質学的データを提供した.
- 巨大な地震の滑り込みと破裂の範囲を制御する要因を理解することは依然として課題です.
研究 の 目的:
- 2011年の東北大震災の破裂の特徴を制御する地質学的構造を調査する.
- 日本北東部におけるメガ・スラストの地震行動と 上層プレート構造を相関させるため
主な方法:
- 日本北東沖の残存地形と重力異常の分析
- 重力モデリングで,重圧板の密度変動を決定する.
- 構造的な境界線と歴史的な地震性および地震滑り分布の相関関係
主要な成果:
- 構造的な境界線を特定した 恐らくは 中央地質学線で 岩の密度が北に増加している
- 境界の北のメガスラストはロックされ,2011年に重要な滑り (> 40m) を経験しています.
- 境界の南のメガスラストは,インターセイミッククリープとマイナー2011のスライドを示しています.
結論:
- 上層板の地質構造と推論された摩擦特性により,メガスラストの結合が制御されます.
- 中央地質学線は地域の地震発生制御の鍵となる.
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