Mount Aso, or Aso-san, is the largest active volcano in Japan and among the largest in the world. It is located at the center of Aso-Kuju National Park in Kumamoto and Oita Prefectures. The volcano lies roughly in the center of Kyushu. Learn more about this one-time super volcano in our travel guide!
The Origins of Mount Aso
Mt Aso consists of 5 peaks (Aso Gotake), Taka-dake, Naka-dake, Neko-dake, Eboshi-dake and Kineshima-dake. The highest point is the summit of Taka-dake which is 1592 m above sea level. Mt Aso was created by successive eruptions, and the first eruption occurred about 300,000 years ago followed by 3 more big eruptions.
The last big eruption was about 90,000 years ago. And there were about 600 cubic meters of volcanic ejecta. And it is said that about half of Kyushu Island was covered by volcanic ashes. Moreover, ashes even flew to Yamaguchi, the southernmost part of Honshu (Japan’s main island).
You can go up to the edge of the crater of Nakadake by shuttle bus (the ropeway has stopped operation in 2016). But please note that service is often suspended because of a higher volcanic activity level.
The Largest Caldera
The eruption also created a huge caldera. The caldera is 25 km across from north to south and is 18 km across east to west. At this size, it is the largest caldera in Japan and also one of the largest in the world. The mountain is a typical complex volcano, composed of an outer rim with a total circumferential length of 128 kilometers, a caldera (circular volcanic basin) with three municipals inside, and five mountains on the central plain.
Komezuka Geosite consists of a perfect cone that is covered in grass and one of the most famous photo spots of Mt. Aso. Kusasenri Meadow used to be a volcano and now has two lakes, from here you can see Komezuka’s perfect shape clearly.
Daikanbo Outlook on the outer rim is the best point from which you can enjoy a panoramic view of the caldera. Do you want to learn more about volcanic activity in general and the formation of Mt. Aso that started 30.000 years ago in particular? Aso Volcano Museum has a great, dynamic exhibition.
About 50,000 people live in the caldera engaging in agriculture and cattle breeding. People have been burning off their fields for hundreds of years, and by doing so, exterminate harmful insects while growing grass for cattle and horses. Because of the burning of the fields, we can enjoy a great view.
It snows in winter, so the peaks will be covered with snow in the wintertime.
Your Japan Tour
As seasoned Japan experts, we create perfect Japan package tours including destinations like Mount Aso. Check out our group tours and private tours, or contact us to start planning your unforgettable holiday to this fascinating country. Japan is full of once-in-a-lifetime experiences, culture, history, nature, and delicious food!
Access Information
Access to the Aso-san Loop Shuttle Bus Station:
There are direct buses from JR Kumamoto and Aso stations.