日本地球惑星科学連合2019年大会

講演情報

[E] ポスター発表

セッション記号 S (固体地球科学) » S-CG 固体地球科学複合領域・一般

[S-CG48] Science of slow earthquakes: Toward unified understandings of whole earthquake process

2019年5月29日(水) 10:45 〜 12:15 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:井出 哲(東京大学大学院理学系研究科地球惑星科学専攻)、廣瀬 仁(神戸大学都市安全研究センター)、氏家 恒太郎(筑波大学生命環境系)、波多野 恭弘(東京大学地震研究所)

[SCG48-P13] Episodic tremor and slip silently invades strongly locked megathrust in the Nankai Trough

*加納 将行1加藤 愛太郎2小原 一成2 (1.東北大学理学研究科、2.東京大学地震研究所)

キーワード:Slow slip events、Slow earthquakes、Western Shikoku、GNSS

Recent seismic and geodetic observations in subduction zones have revealed that slow earthquakes have preceded some large earthquakes (e.g., Kato et al., 2012; Mavrommatis et al., 2014; Ruiz et al., 2014). Characterization of slow earthquakes and their relation to large earthquakes provides important clues to constrain a wide spectrum of slip rates on tectonic faults. In this study, we report new evidence of a slow slip transient at the downdip edge of the strongly locked seismogenic zone in the western Nankai Trough in southwest Japan based on GNSS time series. This slow slip transient was remotely excited during an episodic tremor and slip at the downdip extension of the locked zone. Through this remote triggering, the frequent occurrence of the deep episodic tremor and slip invades the strongly locked megathrust zone and may intermittently increase the probability of large earthquakes in the Nankai Trough.



Acknowledgments

We used GNSS data provided by the Geospatial Information Authority of Japan. This study was supported by the JSPS KAKENHI Grant Number JP15K17743 in Grant-in-Aid for Young Scientists (B), JP18K03796 in Grant-in-Aid for Scientific Research (C), JP16H06473 and JP16H06474 in Scientific Research on Innovative Areas “Science of Slow Earthquakes.”