Amounts of Substances and Heat Energy Discharged from Hot Springs in Japan

Abstract

Amounts of materials and heat energy discharged from hot springs, one of volcanic phenomena, in Japan are discussed. More than 16, 000 hot springs (＞25℃) are known in Japan at present (1972-3-31). About 5, 000 chemical analyses of these waters have been carried out mainly from the medical point of view. Chemical properties of hot springs obtained mainly from about 2, 500 of the reliable analytical data are given. Distributions of temperature, pH, residue on evaporation, chemical components, and also arithmetical mean value, and the central value of log-normal distribution of many components are shown. Total amount of water discharged from hot springs in Japan is more than 6.7×10¹¹ 1/yr (6.7×10¹⁴ g/yr), which is about 0.1% of rain fall. Amout of heat energy discharged is about 2.6×10¹⁶ cal/yr (average temperature 50℃→average air temperature 10℃). Total amount of substances discharged by hot spring water is about 2×10¹² g/yr (2×10⁶ ton/yr) (about 4～5% of that of rivers in Japan). Relation between amount of heat energy and amount of chloride ion discharged from hot springs is estimated to be about Cl=10^-8 ton/kcal, and by this relation the amount of volatile components discharged by volcanic eruption can be estimated.