Numanotaira Crater
Numanotaira Crater on Mt. Bandai was formed during volcanic activity around 2,500 years ago. Mt. Bandai was a symmetrical volcano, but the top of the mountain collapsed in on itself, creating this 1.2-kilometer wide, 350-meter deep crater. After the collapse, the crater was surrounded by four peaks, O Bandai (1,816 m), Kushigamine (1,636 m), Akahaniyama (1,430 m), and Ko Bandai (1,800 m). Another significant eruption in 1888 caused Ko Bandai to collapse, sending landslides cascading down the northern slopes of the mountain and resulting in the creation of the famous Goshikinuma ponds. Today only three peaks comprise the crater wall. The 1888 eruption also opened vents, called fumaroles, in the crater walls, that emit volcanic gases.