Variations in Clast Porosity in the Products of the 2008 Eruption of Kasatochi Volcano, Central Aleutian Islands, Alaska
Abstract
The 7-8 August, 2008 eruption of Kasatochi Volcano, an island stratovolcano located in the Central Aleutian Islands, was the first historically documented eruption of Kasatochi, and produced voluminous pyroclastic flows that blanketed the island and expanded the area of the island by ~30%. These pyroclastic flows also contained juvenile pumiceous clasts with a wide variety of both compositions and textures. More mafic clasts tend to be denser, while more silicic clasts tend to be more vesicular. Mafic clasts also tend to be more crystal-rich than more silicic clasts, especially in terms of groundmass crystallinity; groundmasses of felsic clasts may be nearly crystal free, unlike the microlite-rich groundmasses of the mafic clasts. The objective of this project is to measure and compare bulk densitites, vesicle textures and crystallinities between samples of different bulk compositions, in order to quantitatively test the qualitative descriptions provided above. These measurements may then be used to elucidate how the vesiculation regimes (e.g. nucleation-dominated, growth/coalescence-dominated, etc.) differed between clasts of different bulk compositions. Furthermore, proportions of dense and vesicular material vary throughout the eruption. Changes in the proportions of dense and vesicular material may be linked with variations in explosive behavior observed during the course of the eruption.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.V11C2787L
- Keywords:
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- 8400 VOLCANOLOGY;
- 8404 VOLCANOLOGY / Volcanoclastic deposits