hot spring jigoku, multi-colored volcanic creek with stones in kannawa district in beppu, japan

acid asia beppu boiling creek danger destination district environment famous fumarole gas geological geothermal heat hell hot japan japanese jigoku kannawa kyushu landscape mineral mud multicolored nature oita onsen outdoor place pond pool prefecture sea smell smoke spa spring steam stone stones sulfuric sulphur temperature thermal tourism travel umi unpleasant volcanic water