Location maps of the Nankai Trough and the Shimanto accretionary complex. (a) Map of the Nankai accretionary margin offshore southwest Japan. The orange area and red line indicate the rupture area during the 1944 Tonankai earthquake (M
8.1) and the location of the seismic reflection line in (b), respectively. (b) Seismic reflection profile of the Nankai accretionary prism showing drill sites C0004 and C0007 at the shallow portions of a megasplay fault and plate-boundary thrust, respectively (modified from Moore et al. 2009). (c) Distribution of the Shimanto accretionary complex along the Pacific side of southwest Japan and the Ryukyu Arc.