Fig. 2

a Surface ruptures related to the largest foreshock around Itera and Shimada, identified by high-resolution aerial-photograph interpretation. Map is located in Fig. 1c. The base map is the ortho image of the photograph taken on April 15, 2016, by GSI. We classified the ruptures into the three groups: surface ruptures probably due to faulting, those possibly due to faulting, and the other ruptures, based on whether the location and sense of slip are consistent with those of the mapped active faults. The other ruptures are those we interpreted to be due to ground shaking. The surface ruptures possibly due to faulting have to be examined whether or not they were caused by faulting, based on future surveys. b Surface ruptures related to the largest foreshock and mainshock around Itera and Shimada, identified by high-resolution aerial-photograph interpretation. Map is located in Fig. 1c. The base map is the ortho image of the photograph taken on April 16, 2016, by GSI. The classification criteria of the surface ruptures are the same as a. Details of the surface ruptures except for those described in this study are reported by Kumahara et al. (2016)