The Global Navigation Satellite System network in Japan detected transient crustal deformation along the Nankai trough, Japan, from June 2018. Time-dependent inversion analysis shows that a long-term slow slip event in northern Hyuga-nada Sea along the Nankai trough, Japan, started in June 2018 and decayed in October 2018. From October 2018, a slip area appeared in the Bungo channel and expanded to northern Hyuga-nada Sea and southwest Shikoku at the time of the maximum slip rate. The slip area in the middle of the Bungo channel started to abate around May 2019, with the slip in neighboring areas nearly stopping in August 2019. The estimated rupture propagation is different from those in the past Bungo channel SSEs, in which rupture propagated southwestward from the Shikoku side to the Kyushu Island side at the time of the maximum slip rate. Furthermore, the rupture in northern Hyuga-nada Sea preceded the Bungo channel SSE and reappeared together with the Bungo channel SSE at the time of the 2018–2019 event, though the northern Hyuga-nada Sea SSE followed the 2009–2011 Bungo channel SSE. There is a possibility that the differences in the rupture propagation and recurrence interval from the past events are due to the 2016 Kumamoto earthquake. The adjacent locked area along the Nankai trough subduction zone is a well-known seismic gap and the 2018–2019 SSE changed the stress state in favor of the occurrence of nearby subduction earthquakes.

中文翻译：

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2016 年日本熊本地震延迟的南海海槽长期慢滑事件

日本全球导航卫星系统网络从 2018 年 6 月开始探测到日本南海海槽沿线的瞬时地壳变形。 时变反演分析表明，日本日向滩北部沿南海海槽的长期缓慢滑动事件， 2018 年 6 月开始，2018 年 10 月衰减。从 2018 年 10 月开始，丰后海峡出现滑移区，在滑移率最大时扩展到日向滩北部和四国西南部。丰后水道中部的滑移区在2019年5月左右开始减弱，邻近地区的滑移在2019年8月几乎停止。 估计的破裂扩展与过去的丰后水道SSE不同，其中破裂向西南传播最大滑移率时从四国一侧到九州岛一侧。此外，日向滩北部的破裂先于丰后海峡 SSE，并在 2018-2019 年事件时与丰后海峡 SSE 一起再次出现，尽管日向滩北部 SSE 紧随 2009-2011 年丰后海峡 SSE。与过去事件相比，破裂传播和复发间隔的差异有可能是由于 2016 年熊本地震造成的。沿南海海槽俯冲带相邻的锁定区是一个著名的地震间隙，2018-2019 SSE改变了应力状态，有利于附近俯冲地震的发生。与过去事件相比，破裂传播和复发间隔的差异有可能是由于 2016 年熊本地震造成的。沿南海海槽俯冲带相邻的锁定区是一个著名的地震间隙，2018-2019 SSE改变了应力状态，有利于附近俯冲地震的发生。与过去事件相比，破裂传播和复发间隔的差异有可能是由于 2016 年熊本地震造成的。沿南海海槽俯冲带相邻的锁定区是一个著名的地震间隙，2018-2019 SSE改变了应力状态，有利于附近俯冲地震的发生。