Fig. 1

Map showing the seismic stations where remote triggering has been observed after the Kumamoto earthquake. The stations of JMA network located at Quaternary active volcanoes are plotted as green circles, while the Hi-net (NIED) seismic stations are plotted as blue rectangles. Lighter colors indicate stations where the remote triggering occurred with less confidence (see text for additional explanations). The F-net stations used in Fig. 2b are shown as purple diamonds. Stations with names written nearby, belonging to the Hi-net and JMA networks, are those used in Figs. 2a and 3. The red triangles and gray lines indicate volcanoes and active faults, respectively. The name of some regions in Japan is indicated in gray, uppercase letters; the name of volcanoes close to which remote earthquake triggering has been observed is also indicated (gray letters). The two yellow stars (in the map and inset) indicate the M7.3 earthquake, and one of its immediate larger aftershocks in Oita prefecture occurred toward NE. The inset indicates the mechanism of the mainshock (F-net, NIED), its occurrence time and magnitude, as well as its source fault