Volcanic ash from the June 17, 1962 eruption of Yakedake volcano (photomicrograph, XRD, water-soluble components)

Abstract

Volcanic ash from the June 17, 1962 eruption of the Yakedake volcano was examined by microscopic observation, XRD, and water-soluble components analysis. As a result, pyrite fragments, gypsum, and relatively large amounts of water-soluble components (Cl, SO₄) were detected. These results indicate that this volcanic ash derived from a part of the hydrothermal alteration zone by a phreatic eruption, which supports the previous studies. On the other hand, a photomicrograph including pyrite fragments, the presence of gypsum, and a large amount of water-soluble components newly obtained in this study are presented here because they can be used as reference data in the case of future eruptions.