There is a nature walk that is a 1km long loop. It takes about 30 min. to go around. There are lots of volcanic phenomena to see along the way. So, stay in the safety zone.
In this area alone, there are over 100 fumaroles spewing volcanic gases contains steam, hydrogen sulfide, sulfur dioxide and other compounds. The gas is over 100-degree Celsius and poisonous, so stay a safe distance away. Around the fumaroles can be seen deposits of yellow crystals formed by sulfur contained in the gas.
There is a hot bath with Onsen water, restaurants and hotel.