Tamagawa Onsen (玉川温泉） is one of Japan’s most picturesque hot springs, which a violent volcanic activity is closely observed. Next to the headspring, ohbuki （大噴）, which releases as much as 9,000 liters of radioactive, strong acidic water every minute, there are many yellow rocks with constant gush of steams—fumaroles are the vents that releases steam with crystals formed by condensation of sulfuric gas. The scenery is simply marvelous!
The stream from the headspring, ohbuki, is violent but beautiful!
Stay away. Stay behind the ropes.
Crystalized sulphurs are beautiful on the contrast with the grey earth.
There are more than 100 fumaroles (funkikou) here,
which releases toxic natural gas over 100 degree in Celsius. Stay away.
Some say that it is a reminder of this lively earth. Some others say it looks like another planet. Whatever they may say, you have to see them in person.
More than a hundred of fumaroles exists over the area. Every morning the level of natural gas is measured in order to ensure the safety of guests; but remember—it is natural and could be impulsive!! The ropes are set off so that the guests do not approach the danger too close, but please beware.
BE AWARE! STAY BEHIND THE ROPES!
Otherwise, Tamagawa Onsen is nothing but a unique place which Japan is proud of. The access is not the most convenient, but it is worth a visit. Make sure to plan ahead!