Daideikazan Mud Volcano - “Great Mud Volcano”
This area was once the site of a hot-spring pond. However, sediment from escaping steam filled up the pond, and then occasional eruptions of compressed steam from the mud caused the sediment to pile up. Daideikazan is the largest mud volcano in Japan, growing steadily in size since its formation in 1917–1918. The mud is 8 meters deep, and the ejected material reaches approximately 94.5°C.