鹿児島市に湧出する温泉水・地下水中ラドン濃度と活断層の関係 [in Japanese] Relationship between active faults and 222Rn concentration in Hot springs and Groundwaters around Kagoshima city, Japan [in Japanese]
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Hot spring and groundwater radon concentrations in the vicinity of Kagoshima city area were surveyed to examine relationship with the geological structure such as active fault. Hot spring water temperature suggested that they conform to popular geothermal gradient, suggesting that the hot springs are currently not affected by heat from magma under Aira caldera and old volcanic ejecta. Higher radon concentration in groundwaters discharged from porous pyroclastic flows than that in hot springs from hard bed rocks are obtained. Assuming similar uranium content in both rocks, the higher radon concentration is attributed to difference in porosity. The radon concentration distribution show that the hot springs along the active faults and faults in bed rock have higher concentration, suggesting that the hot springs may be discharging through active and inactive faults. Several hot springs along the faults are considered to be a mixture of meteoric water and magma related water by stable oxygen and hydrogen isotope data, which means that magma related waters are upwelling through active and inactive faults. These results suggest that radon concentration distribution of the hot springs and groundwater strongly associate with their hosting geology and geological structure.
- 鹿児島大学理学部紀要 = Reports of the Faculty of Science, Kagoshima University
鹿児島大学理学部紀要 = Reports of the Faculty of Science, Kagoshima University (51), 52-59, 2018-12-31