1. Obama hot springs, situated on the east coast of Shimabara peninsula, Nagasaki prefecture, are now prosperously utilized for the salt-making industry, and its daily consumption of hot water (9°C-100°C) amounts 60, 000t containing the heat energy 4.6 × 10
9 kcal (equivalent to 750 ton coal). This amount in much excess discharge against the capacity of heat and the transfering velocity, of hydrothermal solutions.
2. Consequently, there have provoked much serious accidents, that is, the areal retrenchment of flowing zone, the fall of the rock temperatune (20°C at the bottom of the bore hole) and others. For these troubles, the temporary restriction of discharge has put in operation, and the recovery indications are now percieved.
3. Analysing these supercritical phenomena, the writer has presumed the dimensions, energies in the order estimating calaulations. The results are as follows :
(a) heat energy of this magma 0.26 × 10
14 Kcal
(b) dimension of this magma 0.06 Km3 (a sphere with 200m radius)
4. From the geochemical point of view, there are very much interesting facts concerning the relation among sea water, ground water, and hydrothemal solutions. The spring water has recently the content of 12, 000 p. p. m. Cl' that is above two-fold of the older spring water. Table 4 shows the ultimate answer about this problem. Potash and silica rich solution is normal in such a condition as alkaline. The juvenile water ratio of this hot spring is as follows :
Juvenile water vadose water
The older spring 67% 33%
The present spring 15% 85%
Therefore its natural steam is too wet and faint for the electric power engineering.
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