The Two Roles of Aso Shrine
Preventing eruptions and ushering in good harvests
The rites and festivals performed at Aso Shrine serve two distinct functions: first, to prevent eruption of the volcano, and second, to ensure bountiful rice harvests.
The two roles are interconnected, since the smoke and ash from even a small eruption could damage crops, livestock, and dwellings over a considerable distance. And since volcanic eruptions often last for months at a time, the cumulative damage can be very serious.
The annual harvest comes around with much greater regularity than volcanic eruptions, so the shrine conducts many more rites and festivals related to growing rice than to calming the crater.