Fig. 3

Calculated density contrast model beneath Aso volcano. a, b, and c are horizontal slices at depths of 3.1, 4.9, and 8.2 km, respectively. Earthquakes within 1 km of the horizontal plane are plotted as yellow dots and green crosses. Yellow dots represent epicenters of earthquakes before the 2016 Kumamoto earthquake (from 2003 to 2015), determined by the JMA. Green crosses represent aftershocks that occurred in the first 3 days after the mainshock (Fig. 1). The shaded gray area in (c) is outside the modeled zone. Density distributions are plotted using linear interpolation