Spatial distributions of coda Q and the S-wave velocity. Spatial distributions of coda Q at frequency bands of (a) 1 to 2 Hz, (b) 2 to 4 Hz, (c) 4 to 8 Hz, (d) 8 to 16 Hz, and (e) 16 to 32 Hz and (f) the perturbation of S-wave velocity at 25-km depth (Matsubara et al. 2008). Gray lines show Quaternary active faults. Dark gray lines show the active faults of the Nobi fault zone. Circles in (a) denote the points at which we sampled values of coda Q and δVS for Figures 4 and 5.