18.North Outer Rim Pyroclastic Flow Geosite

Aso Pyroclastic Flow Deposits (Yamanami Highway)

This flat plateau sits 800 m above sea level, adjacent to Yamanami Highway, which runs from the Ogashiwa district of Ubuyama Village along the border of Aso City. Comprised of deposits from Aso's pyroclastic flow, the plateau is an important site for understanding the early stages of the chain of geological transformations that occurred starting 90,000 years ago.

Nabegataki Falls

Avid television watchers may recognize this waterfall from its frequent appearance in Japanese commercials. Nicknamed "Back-view Falls," visitors can observe the curtain of cascading water from an indentation behind the falls measuring over ten meters deep. The waterfall is 9 m high and 25 across, and falls over a wall of ignimbrite, an Aso pyroclastic flow deposit.

Yusuikyo Gorge

Located in the headwaters of the Chikugo River, this beautiful gorge features exposed bedrock and faults, many waterfalls of all sizes, and abundant springs. The clear water is normally only about 10 cm deep, making it a popular summer water play spot for families. Kids slip and slide in their floats over the large, smooth rocks surrounded by an idyllic setting of natural forest.

Like many of the streams in the northern part of Aso Caldera, Yusuikyo Gorge is formed from ignimbrite, a pyroclastic flow deposit, and has a bedrock river bottom that is free of sand and sediments for over 100 m. The gorge is an excellent place to observe the banded, or eutaxitic, structure of ignimbrite.

Nanataki Falls

These seven waterfalls are located in the lower reaches of Oda River. Promenades offer a close-up view of the waterfall pools, and stone statues of the deities Fudo-myo-o and Bensai-ten are enshrined in the center of the falls.