Mount Aso (阿蘇山, Asosan) is an active composite volcano on the island of Kyushu. Located in Aso Kuju National Park, Mount Aso is approximately 48 kilometers north of Kumamoto City. It is one of the proud symbols of the Kumamoto Prefecture, once known as Hino Kuni (Land of Fire).
This ancient crater ranks among the world’s largest, measuring an astonishing 18 kilometers from east to west, 25 kilometers from north to south, and a circumference of over 100 kilometers. In the center of the caldera stand that mountain’s most active volcanic peaks.
Mount Aso is not only the largest active volcano in Japan, with its peak, Takadake, measuring at 1,592 meters above sea level, but it is also one of the most beautiful in the world. It has one of the largest caldera as well, which is said to have resulted from an explosion roughly 100,000 years ago, spanning a circumference of around 120 kilometers.
To the north of the mountain, a somma forma a bastion of about 300 – 500 meters high in the crater wall. Completely covered with lush greenery, this area is also called the Green Niagara. Further north there are enormous plains that stretch out across a plateau, while in contrast, the south side of Mount Aso features precipitous landforms.
The caldera has a long history of human occupation. Today, about 50,000 Japanese live in its long-established towns and villages. No other caldera in the world has such a large community of people living in it. The caldera contains the city of Aso as well as Aso Takamoricho and South Asomura. Aso’s pyroclastic flow deposits were utilized early on for bridge construction in the region. There are now approximately 320 arched stone bridges in the Kumamoto Prefecture, including the Tsujunkyo and Reidaikyo bridges on the Midorikawa River, which are important national cultural properties.
Apart from Takadake, Mount Aso has four other peaks:
The crater of Mount Nakadake (the west side of which is accessible by road) contains an active volcano which continuously emits smoke and has occasional eruptions. Ejecta from the huge caldera eruption 90,800 years ago covered more than 600 kilometers cubed – which is roughly equal the volume of Mt. Fuji. It is presumed that the pyroclastic flow plateau from the eruption covered half of the island of Kyushu.
Another eruption (which formed the present somma) occurred approximately 300,000 years ago. Four other large scale eruptions occurred during a period extending from 300,000 to 90,000 years ago. As large amounts of pyroclastic flow and volcanic ash were discharged from the volcanic chamber, a huge depression (caldera) was formed as the chamber collapsed. The fourth eruption is said to be the largest, with volcanic ash covering the entire island of Kyushu and even extending to regions of the Yamaguchi Prefecture.
Apart from these active volcanic peaks, the inside of the caldera is actually a green, lush landscape of wide grassy plains that are grazed on by the local wildlife and domesticated cattle. In particular, the outer rim of Nakadake is very peaceful, coated with grassy plains where cows and horses graze. Visitors typically take a relaxing stroll or have a picnic in this area. There are designated camping grounds for tourists as well. In preparation for the heavy cattle grazing that starts in the spring, locals burn the dried grass to help kill off harmful insects. The grassy plain, one of the famed sights at Mount Aso, was kept by this annual burning, which also contributes to the natural spring beauty of the crater.
Portions of the crater area, however, are often partially and sometimes completely closed off to visitors because of the poisonous volcanic gases. These gases can be extremely intense at times (even when the area is open to the public), so people with respiratory problems should refrain from getting too close to the crater.
Not far from the Nakadake crater are the plains of Kusasenri (草千里). These are grassy meadows that run along the northern slopes of Eboshidake. Kusasenri is one of the most popular areas for tourists, where you can enjoy views from the mountains and the lakes from horseback from March to December.
Just off the road that runs from the Aso Volcano Museum to Aso town is the beautifully cone-shaped, extinct volcano of Komezuka. Located on the northern slopes of Nakadake, the Komezuka volcano measures 954 meters, and features sightseeing walking trails in the area (but not to the very top). Unfortunately, easy access by public transportation in this area is not provided.
Mount Aso’s climate data is typically taken at an elevation of about 1,100 meters. At this height there is a noticeable transition between a humid subtropical climate and a humid continental climate with warm summers and cold winters. Precipitation is high throughout the year, and is extremely heavy in June and July with over 500 millimeters of rain falling in each month.
There is a museum in the area of the volcano along with various hot springs, many of which are surrounded by traditional Japanese inns. There are plenty of tourist shops and local restaurants throughout Mount Aso as well.
The Aso Volcano Museum is a small facility for observing and learning about Mount Aso. The Museum is located in a small section of Kusasenri, in the Kumamoto Prefecture.
In the museum you’ll find live images from two cameras positioned right in the crater displayed on a widescreen. This provides visitors with a unique perspective of the volcano they won’t find anywhere else. This “Crater Camera Experience” also features a controllable camera that can provide you with various viewing angles from the mouth of the volcano.
The museum’s third floor is dedicated to the local people of Mount Aso. They have a pretty cool film set up as well that explains what it’s really like living next to an active volcano. The 30,000 years of its history from the formation to the current status of it is portrayed on their kinetic model. For foreigners, there are English-language brochures and a special translated video presentation of the surrounding volcanic activity of Mount Aso.
The Nakadake Crater can be reached in a 30 to 40 minute bus ride from JR Aso Station. There is one bus that comes every 1 or 2 hours. The one way trip to Mount Aso costs 540 yen and is not covered by the Japan Rail Pass. Buses travel only as far as Asosan Nishi Station, from where it is only a short ropeway ride (1000 yen round trip) away to the crater.
If you prefer, you can also walk to the Nakadake crater in about 30 minutes. Cars can drive all the way to a parking lot just next to the crater, but you must pay 560 yen for the last couple of kilometers, which is a toll road.
The Mount Aso Ropeway is a Japanese aerial lift line (cable cars) in Aso, Kumamoto, and is operated by Kyushu Sanko Tourism. This is the most recommended way to reach the crater, although it is not always open for viewing because of the regular emissions of ash and fumes.
When open, the crater can also be visited at night, during which you can actually see the lava seeping out of its fissures creating fiery streaks in the dark.
The official website for Mount Aso Ropeway says it was the first aerial lift in the world to be built on an active volcano. As such, the line and the observatory have unique views of an active volcanic crater with fumes. The cable cars can carry up to 40 passengers at a time and takes about 4 minutes to reach the peak.
Aso Shrine (阿蘇神社) is a Shinto Shrine in Aso, Kumamoto Prefecture, Japan. It is one of the oldest and most prominent Shinto shrines in Japan. Aso Shrine holds several important cultural properties, including Ichi-no-shinden (一の神殿), Ni-no-shinden (二の神殿), and Romon (楼門).
Aso Shrine at Mount Aso in Kyushu is traditionally held to have been a center of Shinto worship before the accession of Emperor Jinmu. The shikinaisha shrine complex at Ichinomiya, in what is today known as the Kumamoto prefecture, was established in 281.
Official records link the founding of the Aso Shrine to the reign of Emperor Keiko. By the middle of the 11th century, the shrine was involved in a number of national issues as they played out across the island of Kyushu. During the ascendancy of the Kamakura shogunate, the Hojo clan held a significant influence over the affairs of Aso Shrine.
The shrine is actually dedicated to the veneration of Tateiwatatsu-no-Mikoto, who was a grandson of Japan’s very first emperor and the brother of Emperor Suizei, the second monarch on the traditional list of emperors. In the same period that Emperor Jimmu was establishing his palace at Kashihara at the foot of Mount Unebi in Yamato province, Tateiwatasu was sent to Aso where he helped establish a number of agricultural communities; and later, he is said to have built a palace at Miyagi.
The original location of Aso shrine is uncertain because it was destroyed and rebuilt many times in or near the crater of Mount Aso. The present buildings date only from the Tenpo era (1830–1843).
Aso was the chief Shinto shrine (Ichinomiya) of the old Higo Province. It serves today as one of the Ichinomiya of Kumamoto Prefecture.
From 1871 through 1946, the Aso Shrine was officially designated one of the Kanpei-taisha (官幣大社), meaning that it stood in the first rank of government supported shrines.
Aso no Okami, the kami or spirit who dwells at Aso Shrine has been worshipped from early times as the guardian deity of safety in navigation, and today, Aso no Okami is popular as a god protecting worshippers from traffic accidents and other untoward events.
Yabusame is an annual festival that brings together horse-mounted archers, special arrows and targets, and Shinto ritual at Aso Shrine.
The Aso no Himatsuri festival has its origin in the month of March festivals such as Aso no Noyaki (the first burning in Aso) and Aso jinja no Hifurishinji (the fire ritual of Aso Shrine). Although rarely performed today, ceremonies which honor ancestors who settled near the Aso caldera do continue to be associated with the Aso jinja.