Figure 2
From: The size range of bubbles that produce ash during explosive volcanic eruptions
Features of simple and complex ash particles. (a) and (b) Simple ash particles from Mount St. Helens, showing partial vesicle imprints preserved adjacent to fragmented vesicle walls and plateau borders, which allow the imprint of a single vesicle to be measured per individual grain; and (c) and (d) complex ash particles, also from Mount St. Helens, which preserve the imprints of multiple vesicles on a single grain and may also contain complete, unfragmented vesicles in their interiors. Simple ash particles are typically smaller than complex ash particles.