Japan Geoscience Union Meeting 2019

Presentation information

[E] Poster

S (Solid Earth Sciences ) » S-CG Complex & General

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

Wed. May 29, 2019 10:45 AM - 12:15 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Satoshi Ide(Department of Earth an Planetary Science, University of Tokyo), Hitoshi Hirose(Research Center for Urban Safety and Security, Kobe University), Kohtaro Ujiie(Graduate School of Life and Environmental Sciences, University of Tsukuba), Takahiro Hatano(Earthquake Research Institute, University of Tokyo)

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

*Masayuki Kano1, Aitaro Kato2, Kazushige Obara2 (1.Graduate school of science, Tohoku University, 2.Earthquake Research Institute, The University of Tokyo)

Keywords: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.


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.”