These barren fields of hot springs contain many steam vents, bubbling mud pits and fumaroles.

[3] In an older, now dormant hot springs field, paths lead to the Manmyoji Temple and to the Unzen Disaster Museum, that commemorates the eruptions that occurred in the 1990s in which 12,000 people were evacuated and over 40 people perished.

[3] The hot mineral water has a high sulfur content, and strong levels of acidity.

[2][4] In addition to sulfur, the mineral content includes aluminum, iron, and sulfate.

The water temperature is 98 °C, and the hot carbonate and hydrogen sulfide gasses that erupt from the springs can be as high as 120 °C.