Fig. 5.

Juvenile “fresh pumice” ((a) and (c)) and “fresh lava” (b) in January 19, 2011 ash (collected at Site No. 8; Fig. 1 and Table 1). (a) and (b) are from 250–500 μm fraction, while (c) is from 500–1000 μm fraction. (a) and (b) are photographs taken under binocular microscope, while (c) is BSE image of thin section. For definition of each ash component, see Subsection 5.1.1. Note denser “fresh lava” particles have darker color than fresh pumice particles ((a) and (b)). As shown in (c), the “fresh pumice” has low vesicularity and blocky shape, implying magma interaction with aquifer. In (c), pyroxene and Fe-Ti oxide phenocrysts are present. Like the “fresh pumice” particles, “fresh lava” particles in (b) are glassy. Color version available online.