Many kinds of substances (solids and volatiles) have been discharged by volcanic phenomena such as volcanic eruption, fumarolic activity and hot-spring activity. Usually the amounts of volcanic products have been estimated only by measuring the amounts of residual solid products after volcanic eruptions. However, they are not the total amounts of volcanic products, because they have not contained the tremendous amounts of volcanic gases discharged at volcanic eruptions. Then, in this paper, the method for the determination of volatile components of volcanic products discharged by volcanic action are proposed. Relation between amounts of heat energy and amounts of chloride ion discharged from hot springs in Japan is estimated to be about Cl=10-8 ton/Kcal (Iwasaki et al 1963). The total amount of chloride ion discharged from hot springs in Japan is estimated by this relation to be 9.3x1011 g/yr, which is very near the calculated value 8x1011 g/yr obtained from water discharge and the average content of chloride of hot springs in Japan.
