Mt. Bandai
Mt. Bandai is a 1,816-meter stratovolcano, a volcano built up of layers of lava and ash, that has been dramatically reshaped by two large eruptions.
Around 2,500 years ago, Mt. Bandai was symmetrical, but volcanic activity caused the peak to collapse in on itself, creating the Numanodaira Caldera.
In 1888 it erupted again in a devastating steam-blast eruption, an explosion that occurs when water beneath the ground or on the surface is heated by magma or lava. No lava was discharged, but it was powerful enough to cause the collapse of one of the volcano’s four peaks, Ko Bandai (around 1,800 meters, on the north side of the mountain), and triggered a large-scale landslide.
The landslide destroyed 11 communities and entirely reshaped the north side of the mountain, known today as Urabandai. The landslide that followed destroyed entire villages and dammed up valleys, forming around 300 lakes and ponds. Today, their beauty is a major attraction in Bandai-Asahi National Park.
Vegetation in the area was badly damaged but grew back quickly, in part because of extensive, government-backed reforestation projects. A lava eruption would have likely caused more long-term damage to the ecosystem.
Six trails of varying difficulty lead to the top of the mountain. From the top you can see where Ko Bandai collapsed and the surfaces of lakes and ponds. Since the early seventh century, these trails have been used by practitioners of Shugendo, a folk-religion based on mountain worship, that involves enduring extreme physical hardships. During climbing season, between late May and October, you can follow their footsteps up the mountain’s trails.
Mt. Bandai is made up of hardened layers of lava, ash, pumice, and fragmented rock. Its partial collapse offers a rare opportunity to see a cross-section of this type of volcano, which makes it an important geological site. Mt. Bandai now consists of three peaks, O Bandai (1,816 meters), Kushigamine (1,636 meters) and Akahaniyama (1,430 meters).