Size Distributions and Mineralogy of Ash Particles in the Stratosphere from Eruptions of Mount St. Helens

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Science  20 Feb 1981:
Vol. 211, Issue 4484, pp. 832-834
DOI: 10.1126/science.211.4484.832


Samples from the stratosphere obtained by U-2 aircraft after the first three major eruptions of Mount St. Helens contained large globules of liquid acid and ash. Because of their large size, these globules had disappeared from the lower stratosphere by late June 1980, leaving behind only smaller acid droplets. Particle-size distributions and mineralogy of the stratospheric ash grains demonstrate in-homogeneity in the eruption clouds.