loading page

Slow slip events in the Kanto and Tokai regions of central Japan detected using GNSS data during 1994-2020
  • Takuya Nishimura
Takuya Nishimura
Kyoto University

Corresponding Author:nishimura.takuya.4s@kyoto-u.ac.jp

Author Profile


Slow slip events (SSEs) along subduction zones play an important role in accommodating relative plate motion. SSEs interplay with large megathrust earthquakes and other slow earthquakes, including low frequency and very low frequency earthquakes. The Kanto and Tokai regions of central Japan host frequent slow and large earthquakes, with significant differences in slip behavior along the subduction zones in the Suruga Trough, Sagami Trough, and Japan Trench. In this study, we conducted a systematic search to estimate the fault models and durations of short-term SSEs using continuous Global Navigation Satellite System (GNSS) data collected from 1994 to 2020. We detected 179 potential SSEs with moment magnitudes of 5.3–7.0 and durations of 0–80 days from the time series. Along the Sagami Trough, two shallow regions at a depth of 10–20 km host Mw ≥ 6.5 SSEs off of the Boso Peninsula and accommodate most of the relative plate motion aseismically. Some SSEs also occur on the deep plate interface down to ~50 km without low frequency tremors (LFTs). Along the Japan Trench, the cumulative slip of the SSEs exhibits a bi-modal depth distribution to avoid the large slip areas of past megathrust earthquakes at 30–40 km depth. The shallow SSEs are in the same depth range (10–30 km) as LFTs, but are spatially separate from LFTs along the trench. The detected SSEs have limited temporal correlations with other slow earthquakes and earthquake swarms, which suggests that many factors control the genesis of slow and regular earthquakes.
Feb 2021Published in Geochemistry, Geophysics, Geosystems volume 22 issue 2. 10.1029/2020GC009329