Spatiotemporal Evolution of Long‐ and Short‐Term Slow Slip Events in the Tokai Region, Central Japan, Estimated From a Very Dense GNSS Network During 2013?2016
Spatiotemporal Evolution of Long‐ and Short‐Term Slow Slip Events in the Tokai Region, Central Japan, Estimated From a Very Dense GNSS Network During 2013?2016
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根据 2013 年至 2016 年期间非常密集的 GNSS 网络估算的日本中部东海地区长期和短期慢滑移事件的时空演变
DOI：
10.1029/2019jb018650
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
Kato Teruyuki
中科院分区：
文献类型：
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作者：
Sakaue Hiromu;Nishimura Takuya;Fukuda Jun'ichi;Kato Teruyuki
利用2008年1月1日至2016年1月31日的全球导航卫星系统（GNSS）数据分析了南开俯冲带东海地区的长期和短期慢滑事件。该数据集包括我们新的临时站点，以获得高分辨率观测，站点间距约为5公里。在过去的二十年中，东海地区已经报道了长期和短期sse。由于长期sss主要通过GNSS观测，而短期sss主要通过倾斜仪和应变仪观测，因此难以直接比较。我们对GNSS数据进行了改进时间分辨率的时间相关反演，并成功地获得了长期和短期sss的时空演变。我们的研究结果显示Mw6.6的长期SSE非常缓慢和稳定的滑动，以及与短期SSE （Mw6.0-6.1）相关的几次加速滑动。我们的研究结果显示了短期地震的迁移滑动模式和滑动率的细节，以及与低频震颤（LFT）的可能关系。与较大的长期sse相比，LFT与较小的短期sse更相关。然而，短期sse的最大日滑移率比长期sse的大一个数量级。这暗示了一种解释，即LFT可能与短期sse对板界面的加载直接相关。
We analyzed Global Navigation Satellite System (GNSS) data from 1 January 2008 to 31 January 2016 for the Tokai region of the Nankai subduction zone, in order to study long‐ and short‐term slow slip events (SSEs) on the subduction interface. The dataset included our new temporary stations to obtain high resolution observations with station spacing of about 5 km. Long‐ and short‐term SSEs have been reported in the Tokai region, over the past two decades. It is difficult to directly compare those SSEs because long‐term SSEs were observed by GNSS, while short‐term SSEs were mainly observed by tiltmeters and strainmeters. We applied a time‐dependent inversion with improved temporal resolution to GNSS data and successfully obtained the spatiotemporal evolution of long‐ and short‐term SSEs. Our results show the very slow and stable slip of a long‐term SSE with Mw6.6, along with several episodes of accelerated slip associated with short‐term SSEs (Mw6.0–6.1). Our results showed the details of the migrating slip patterns and slip rates for the short‐term SSEs and possible relation with low frequency tremor (LFT). LFT is more associated with smaller magnitude short‐term SSEs rather than the larger long‐term SSEs. However, the maximum daily slip rates for short‐term SSEs are an order of magnitude larger than those for the long‐term SSEs. This suggests an explanation that the LFT may be directly related to the loading of the plate interface by the short‐term SSEs.