Fig. 1
From: Two long-term slow slip events around Tokyo Bay found by GNSS observation during 1996–2011
The study area and an example of the GNSS data. a PA, OK, PH and AM denote the Pacific, Okhotsk, Philippine Sea and Amurian plates, respectively. The red arrows represent secular velocities of the oceanic plates relative to OK (Nishimura et al. 2007). In the area marked by the blue circle, large coseismic displacements were observed due to the M9 earthquake on March 11, 2011. The green circle denotes the area where a transient acceleration occurred during 1996–2011 (Mavrommatis et al. 2014). The red rectangle shows the study area, which is magnified below. b The diamonds and the black arrows denote the GNSS sites and linear background trends during 1996–2011, respectively. The orange/pink curves represent the contours of the plate boundary between OK and PA/PH (Hirose et al. 2008; Nakajima et al. 2009). The area surrounded by the green curve denotes the asperity of the 1923 Kanto earthquake. The red rectangle represents the area where a short-term SSE occurred (Hirose et al. 2000). c, d Examples of the detrended GNSS time-series data with the common errors and the episodic crustal deformations being removed (daily values)