1975 年 20 巻 TOKUBE 号 p. 319-329
In this paper, it is intended to obtain information on the interior of the earth on the basis of chemical nature of volcanic gases. It seems impossible, however, to get any information on the interior of the earth without understanding volcahic gases themselves. To start with, analyses of volcanic gases are mentioned briefly followed by the presentation of a marked individuality of volcanic gases. On the basis of these knowledge, origin of volcanic gases is discussed in connection with the nature of magma. An emphasis was made on volcanic gases as degassing products from the earth. The possibility that N2/Ar ratio of volcanic gases is a useful parameter which characterizes volcanoes in relation to global tectonics is discussed. Finally prediction of eruption through volcanic gases is mentioned.