日本地球惑星科学連合2018年大会

講演情報

[JJ] Eveningポスター発表

セッション記号 S (固体地球科学) » S-SS 地震学

[S-SS15] 地震発生の物理・断層のレオロジー

2018年5月21日(月) 17:15 〜 18:30 ポスター会場 (幕張メッセ国際展示場 7ホール)

コンビーナ:向吉 秀樹(島根大学大学院総合理工学研究科地球資源環境学領域)、谷川 亘(国立研究開発法人海洋研究開発機構高知コア研究所)、松澤 孝紀(国立研究開発法人 防災科学技術研究所、共同)、吉田 圭佑(東北大学理学研究科附属地震噴火予知研究観測センター)

[SSS15-P20] Dynamic Rupture Simulations to Study the Behavior of the M7-M8 Class Earthquakes

*arzpeima samaneh1津田 健一1小川 幸雄1渡辺 孝英1宮腰 淳一1岩瀬 聡2佐々木 哲郎2原田 怜2Ampuero J-P3 (1.㈱大崎総合研究所、2.中部電力株式会社、3.カリフォルニア工科大学、地震学教室)

キーワード:沈み込み帯地震、複数アスペリティ、動力学シミュレーション、連動破壊

The fault rupture of the 2011 Off the Pacific Coast of Tohoku earthquake (Tohoku earthquake, Mw 9.0) ruptured huge amount of area along the Japan trench, including the area close to the trench, where large slip during the main shock was detected, as well as the Miyagi-Oki area around 30 km deep, which radiated short period energy, and their magnitude is usually M7-M8 class earthquakes, such as the historical Miyagi-Oki earthquakes (1978 and 1937).

The rupture of more than one asperity is a prominent phenomenon seen on the large subduction megathrust earthquakes. Understanding the parameters that control the simultaneous failure of multiple asperities, hence maximum magnitude and slip are very crucial for developing scenarios for the M7-M8 class earthquakes.

In this study, we focused on the behavior of the deep asperities from Tsuda et al. (2017) that host M7-M8 class earthquakes. We have simulated dynamic rupture propagation by varying features of the asperities, like their spacing, depth, and values of stress drop and strength drop. Then we make a comparison between these behaviors and the historical earthquakes, such as 1944 Tonankai (M 7.8) and the 1946 Nankai earthquakes (M8.4).