The Underground Geyser Center is a recently built facility found in Youkai Mountain. The kappa conduct a variety of experiments and research projects in the area. Utsuho can be found here supervising research on nuclear energy.
An entranceway to the Underground Geyser Center as seen in Touhou Hisoutensoku
A passageway within the Underground Geyser Center as seen in Touhou Hisoutensoku
The Reactor Core of the Underground Geyser Center as seen in Touhou Hisoutensoku