Fig. 5

(a) Cross-section of Poisson’s ratio structure near the tremor source area, after Tahara et al. (2008). The gray rectangle at the top of the cross-section represents land area. The black dashed line represents the Moho discontinuity. The red and blue lines demarcate the plate boundary estimated by Yagi and Kikuchi (2003), showing co-seismic, and aseismic, slip, respectively. The white dots indicate the distribution of ordinary earthquakes. Tremor distribution is superimposed. The red and blue bars are the estimated depth of tremors based on S-P times, and based on the envelope correlation method, respectively. The two red stars indicate the hypocenters of LFEs relocated by Yoshioka et al. (2008). (b) Cross-section of V _p /V _s distribution near the tremor source area, after Hirose et al. (2008). The gray rectangle at the top of the cross-section represents land area. The red triangle indicates the location of an active volcano. The red line demarcates the plate interface estimated by Hirose et al. (2008). Black dots indicate the distribution of ordinary earthquakes. Red dots are LFEs, including volcanic ones, detected by JMA and relocated by Hirose et al. (2008). The thick dashed line represents the Moho discontinuity. The thin dashed line represents the boundary between low- and high-V _p /V _s zones. Tremor distribution is also superimposed as for (a). (Reprinted from Phys. Earth Planet. Inter., 167, M. Tahara et al., Seismic velocity structure around the Hyuganada region, Southwest Japan, derived from seismic tomography using land and OBS data and its implications for interplate coupling and vertical crustal uplift, 19–33, Copyright (2008), with permission from Elsevier.)