On February 4th 2016, Miyazaki Prefecture launched a press release concerning Mt. Ioyama. Some parts of the trails of Mt. Ioyama near the crater will be closed due to the fact that hydrogen sulfite has been observed from the fumaroles. The period of regulation starts from February 4th from 14:00 hours until safety has been confirmed by research carried out. Parts of the mountain trails of the Ioyama crater will be off-limit. However, other parts of Mt. Ioyama, surrounding roads, such as route 1, and the trail to Mt. Karakunidake will be open as usual.