A preliminary assessment of the abundance of supercritical geothermal fluid using petrological methods: Cases of Kakkonda geothermal field and Aso volcano

Abstract

I estimated the abundance of geothermal resources (geothermal fluid) for Kakkonda and Aso Nakadake using the petrological method. In the Kakkonda area, the estimated geothermal fluid is a flux of 0.5 to 16 M tons/year, with a temperature of 600 to 700°C. In addition, during the formation of the Kakkonda granite via crystallization of basaltic magma, an extremely large amount of, equivalent to about 50 vol.% liquid water relative to that of the Kakkonda hot rock body, geothermal fluid was potentially released. This geothermal fluid may have played an important role in the generation of the hydrothermal system of Kakkonda. The estimated geothermal fluid annually released from Nakadake, Aso, is 9 M tons with a temperature of 1050°C.