Condition of Magma chamber and eruptive process of Ofunato scoria in Ofunato stage, Miyakejima volcano

Abstract

High-pressure melting experiments and analyses of zoning profile on olivine phenocrysts were performed to estimate conditions of magma chamber and the time scale from ascent of magma to eruption. Temperature, pressure and H₂O content in melt for magma chamber condition were ~1100°C, ~150MPa, 3.0wt.%, respectively. Magma might ascend to shallower part and remain for a few days to a few dozen days before eruption.