Fumaroles and Mud Pots
This area was once heavily mined for sulfur, and the presence of sulfur can be seen (and smelt) throughout the area. The majority of the sulfuric gas is emitted by fumaroles—holes from which hot gases and vapors escape. There are also many small-scale mud pots with no exit cavities, which bubble and boil. As at Kon-ya Jigoku, another pond of hot mud, the components of the escaping steam here dissolve in groundwater and become sediment. Heated by the steam, this sediment reaches a temperature of 93.8°C. The mud pots are also highly acidic, with pH levels of 1.6 to 2.2.