Fig. 1
a Map of the Kyushu district. Red dots indicate epicenters of earthquakes that occurred during April 14 and April 30, 2016. b Topographic relief map of the seismic area for the 2016 Kumamoto Earthquake. Yellow circles indicate epicenters of earthquakes that occurred during April 14 and April 30, 2016. Depicted focal mechanisms are shown about earthquakes with magnitude exceeding MJMA4.0. An index number attached to an earthquake magnitude corresponds to an earthquake shown in Fig. 3. Light blue curves indicate active faults cataloged in the digital map of active faults (Nakata and Imaizumi, 2002). Purple dashed boxes show the fault segments estimated in this study, and thick lines on their boxes indicate their upper margins. Red triangles indicate locations of the Nakadake crater and the Kusasenri. Red circle indicates the location of deformation source by Sudo et al. (2006)