Helium isotope analyses of gas and water from Aso caldera and Unzen stratovolcano, South West Japan

Relationships between distances from volcanic cones and helium isotope ratios around several volcanoes. The file includes data from Mt. Aso, Unzen, Ontake, Nevado del Ruiz, Kusatsu-Shirane and Hakone. The dataset was mainly used for investigations of geothermal system at Mt. Aso and Unzen in the publication, \"Older magma at Aso caldera than at Unzen stratovolcano in south west Japan as recorded through helium isotopes\".