Fig. 9

Distribution of sediment fills. a Map for the entire Japan Trench. The areas within the black dashed rectangles are shown in panels b and c. b Enlarged map of the southern part of the Japan Trench. c Enlarged map of the central and northern parts of the Japan Trench. Distribution and thickness of the graben and trench fills are shown (color scale). Note that the range of the color scale is different from that for total sediment thickness (Fig. 8). The background map is a gray-shaded bathymetric map. The yellow line indicates the base of the landward slope. The thin white lines indicate the seismic lines, and the thick black lines indicate the seismic profiles shown in Figs. 10 and 11. Magenta contours show the slip distribution during the Tohoku earthquake (Iinuma et al. 2012), same as Fig. 1. Orange dashed lines with arrowheads indicate the three segments inferred in this study. The same figure with the red-relief image as the background map is shown in Additional file 4: Fig. S4