日本 の 東北 部 で 周期 的 な 緩慢 な 滑り込み が 巨大 地震 を 引き起こし て いる
Naoki Uchida1, Takeshi Iinuma2, Robert M Nadeau3
1Graduate School of Science and International Research Institute of Disaster Science, Tohoku University, 6-6, Aramaki-aza-aoba, Aoba-ku, Sendai 980-8578, Japan.
まとめ
日本におけるほぼ周期的なスロースリップ現象
科学分野:
- 地理学
- 構造学
- 地震学
背景:
- プレート境界断層は,地震と無地震の滑りを通して相対的な動きに対応します.
- 日本北東部では,アセイミックスリップには,アフタースリップと,結合されていない潜水推力領域の安定したスリップが含まれています.
研究 の 目的:
- メガ・スラスト・ゾーンでの 準周期的なスロー・スライドを報告する
- ゆっくりと滑り落ちる出来事と 大きな地震の関係を調べるため
主な方法:
- 地質学的データを分析して,スロースリップ現象を特定する.
- 遅い滑りイベントのタイミングと地震活動の相関関係.
主要な成果:
- 広範囲に広がり,以前は認識されていなかった準周期的なスロースリップの行動が,メガスラストゾーンで特定されました.
- スロースリップは1~6年ごとに再発する.
- これらのイベントは,2011年のM 9 東北地震を含む大規模な地震 (M ≥ 5) のクラスターと一致するか,それより前に起こる.
結論:
- 定期的なスロースリップは 定期的なストレス変化を引き起こす可能性があります
- ゆっくりと滑り落ちる地震は より大きな地震のタイミングを調整します
- ゆっくりと滑る周期性により,時間依存の地震予測が改善されます.
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