It was formed in the wake of volcanic eruption about 200-thousand years ago.

As it was full of mist all year round, it was thought to be a superstitious place where a witch dwelled in.
People were afraid of getting close to it.

Later, it was found that the hot water from this basined place was actually a kind of hot spring, green sulfur.
In other words, it was the upstream source of green-sulfur hot spring.

Main points for knowing Geo-thermal Valley are as follows:

1.   It was exploited in 1911.

2.   Temperature at outlet is almost 100 d/c; other parts are 60-70d/c.

Average is more than 80d/c.

3.   PH index is 1.4, namely, it belongs to acid hot spring.

4.   Size of this area is about 3,500m2

5.   Daily output of hot spring is about 2000 cubic meters.