Fig. 1

Map around the summit of Mt. Ontake, based on the digital topographic data published by the Geospatial Information Authority of Japan. The filled circles indicate the craters of the 2014 eruption. The inner and outer dotted lines denote the range of 1 km and 3 km from the crater area, respectively. The casualties were discovered within the 1 km region (Tsunematsu et al. 2016)