Most hot springs were created
by volcanic heat warming up
underground water and rain water,
however at Arima Onsen, seawater from the Pacific Ocean is heated
by the mantle and gushes out from the ground of Arima.
The Philippine Sea Plate that burrows under the Japanese archipelagoand seawater sink together into the upper mantle at a depth of about 60km.
This location is extremely hot where rocks will melt into magma.
The seawater becoming supercritical somewhere between
and high pressure absorbs various substances in the ground and has been gushing out at Arima over 6 million years.
For this reason, the concentration of salt is twice the amount of seawater.
There are very few hot springs that in the same manner as Arima Onsen,
gushes out from the mantle 60km deep underground
and is also geologically extremely rare in the world.
According to the hot springs analysis of the Ministry of Environment,
Arima Onsen has 7 out of the 9 principal components designated for medical treatment fountains
even one of the very few efficacy
rich hot springs on earth.
Kinsen is originally colorless and transparent
however, because of the oxidation
that turns the metal components reddish when exposed to air; it has
become to be called Kinsen.
The salt content is high at 1.5 to 2 times that of seawater and the salt will adhere to the skin forming a film that moisturizes and the effect of the hot springs is maintained.
The colorless transparent Ginsen is a radiation springs containing trace amounts of radon that is beneficial to the body.
It promotes cell activity, enhances the immune system, and relieves muscle pain and fatigue. Additionally, when inhaled by the respiratory organs, it reaches the entire body and enhances the natural healing power.