Lake Akan has a mud volcano around Lake Akan Onsen Town.
The mud volcano is "Bokke." It keeps volcanic activity still now. The admission fee is free.
The bubbles come up from underground with mud, and smell sulfur. They have over 100℃, so there are fences around there.
The Bokke derives from an Ainu word, "Pofuke", which means "a boiling spot." The Ainu are native Hokkaido People.
To Lake Akan, you have to use a chartered taxi, or bus from Kushiro Airport or Kushiro Station.
After arriving there, please go to Akan Eco Museum at first. Then, walk 350m from the Museum. You can watch smoke, and smell sulfur. That's the destination.
https://www.youtube.com/watch?v=nQWQGDlpo1w
