Figure 10
From: The size range of bubbles that produce ash during explosive volcanic eruptions
Bubble size distributions (BSD) and bubble number densities (BND) of complex ash particles. (a) Fuego samples; and (b) Mount St. Helens samples. Upper plots show the number densities of the bubble volumes while the lower plots show the volume fraction density of the bubble volumes. Although the smaller bubbles dominate the number density, the larger bubbles dominate the volume fraction. The red line indicates the probability density function (function fit), which is defined in the text. In (b) the yellow box shows the dominant (smaller) bubble size mode while the magenta box shows the larger bubble size mode with (c) showing the respective bubble diameters in the distributions measured by Klug and Cashman (1994) on gray and white pumice from the 1980 Mount St. Helens eruption.