Figure 4

Cross-sectional views of λ _v for the case of uniform stress. The averaged values of λ _v are shown by the color scale at the bottom right. The background color shows the S-wave velocity perturbation by Okada et al. (2010) (scale is shown at the bottom left). Locations of cross-sections are shown in the insert map with the label of (a) to (f). The gray lines show the mainshock fault planes by Iinuma et al. (2009). The thin broken line denotes the Moho discontinuity (Zhao et al. 1990). Black circles show deep low-frequency earthquakes.