[1poster01-02] T1.［トピック］広域観測・微視的実験連携による沈み込み帯地震研究の新展開

[T1-P-2] （エントリー）孔内観測とDONETから捉えられた2020年3月の熊野灘スロースリップイベントに対する黒潮蛇行の影響に関する考察

*有吉 慶介¹、木村 俊則¹、宮澤 泰正¹、バーラモフ セルゲイ¹、飯沼 卓史¹、永野 憲¹、ゴンバーグ ジョアン^2,3、荒木 英一郎¹、美山 透¹、末木 健太郎¹、矢田 修一郎¹、堀 高峰¹、高橋 成実^4,1、小平 秀一¹ (1. 海洋研究開発機構、2. 米国地質調査所、3. ワシントン大学、4. 防災科学技術研究所)

キーワード：スロー地震、黒潮蛇行、海溝型巨大地震、南海トラフ

In our recent study, we detected the pore pressure change due to the slow slip event (SSE) in March 2020 at the two borehole stations (C0002 and C0010), where the other borehole (C0006) close to the Nankai Trough seems not because of instrumental drift for the reference pressure on the seafloor to remove non-crustal deformation such as tidal and oceanic fluctuations. To overcome this problem, we use the seafloor pressure gauges of cabled network (DONET) stations nearby boreholes instead of the reference by introducing time lag between them. We confirm that the time lag is explained from superposition of theoretical tide modes. By applying this method to the pore pressure during the SSE, we find pore pressure change at C0006 about 0.6 hPa. We also investigate the impact of seafloor pressure due to ocean fluctuation on the basis of ocean modeling, which suggests that the decrease of effective normal stress from the onset to the termination of the SSE is explained by Kuroshio meander and may promote updip slip migration, and that the increase of effective normal stress for the short-term ocean fluctuation may terminate the SSE as observed in the Hikurangi subduction zone.