HYDROTHERMAL SYSTEM IN YUFUIN GEOTHERMAL FIELD, OITA PREFECTURE

Abstract

In Yufuin geothermal field, there are about 300 spa sources having a total daily discharge of 13, 000 m^3. Karube (1950) shew that the origin of hot springs seems to have the same in all under the ground by mean of the relations among Cl, HCO3 and SO4 ions in the waters. Recently, the developments of spa resources have been carried out in the geothermal field and the spa sources have been increased in every place. New the writer carried out the geochemical research again, and it is found that the thermal waters in this region are fed from two different origins of the hydrothermal waters.