Fig. 2

GNSS time series data, including displacements associated with long-term slow slip events (SSEs), at all 26 stations (Fig. 1) used for the inversion analysis. The black dots indicate processed time series data after removing coseismic steps, steps associated with antenna exchange, linear trends, annual and semiannual variations, and common-mode errors. Each yellow–green curve is the best-fit curve for the processed data. The time span between the two pink vertical dashed lines is 2018.5–2021.7, during which the L-SSE was considered to have taken place. The location of each station is shown in Additional file 1: Table S1. a–c Time series data at the GNSS stations indicated by the red solid circles in Fig. 1. d–f Time series data at the GNSS stations indicated by the blue solid circles in Fig. 1. a, d North‒south component. b, e East‒west component. c, f Vertical component