Geosite introduction of Aso

17.Oshito-ishi Geosite

Oshito-ishi Geosite

Fusion of nature and culture

The tip of an andesite mountain buried in pyroclastic flow is visible at this geosite. The group of megaliths lined up on the peak is believed to have been a site for religious rites in ancient times. The megaliths may also be intrusive rocks (magma rocks that intrude into older rocks).


This cluster of andesite megaliths stands 845 m above sea level atop rolling hills. The largest is a pyramid-shaped rock 5.5 m high and 15.3 m around. Since ancient times local people have worshipped the rocks as sacred. The grasslands of the outer rim's pyroclastic flow plateau are visible from the hilltop.