S1: Earth materials science in igneous processes (Special Session)

[S1-06] The color of volcanic glass: A case study of ash from the 2018 eruption of Shinmoedake volcano, Japan

*Keiko Matsumoto¹ (1. Geological Survey of Japan, AIST)

Keywords:volcanic glass, color, Shinmoedake volcano, Raman spectroscopy

The colorization mechanism of volcanic glass during volcanic processes was investigated for the ash from the 2018 eruption of Shinmoedake volcano. Raman spectra of black transparent particles of March 6–7th eruption show a peak at 690 cm^-1 due to iron-bearing nanolites occurrence, while that of pale gray transparent particles were smooth. Since precipitation of the nanolites increases melt viscosity, the black color of the particles indicates higher viscosity during the lava effusion stage.