Fig. 1

Seismic observations from the Metropolitan Seismic Observation network (MeSO-net) in the Kanto region, Japan. a Seismic stations and depth contours of subducting slabs. The magenta and yellow squares denote the locations of MeSO-net stations (NIED 2021). Seventy-two stations (magenta squares) in a region 10 km wide along the pseudo-survey line (black bold line) are used for seismic imaging in this case study. The red and blue lines denote the depth contours of the Philippine Sea (PHS) slab and the Pacific (PAC) slab, respectively (Nakajima and Hasegawa 2006; Hirose et al. 2008; Nakajima et al. 2009). b Example of the earthquake records at the selected stations along the pseudo-survey line. Several coherent phases are observed after the P wave arrival, which should contain available reflections between the free-surface and subsurface boundaries