Developments in analysis of basaltic ash applied to recent activity at Etna and Stromboli volcanoes
Abstract
Advances in analytical techniques coupled with recent high levels of activity at Etna and Stromboli have offered a unique opportunity to sample and analyze of basaltic ash particles. We have performed new micro-scale analysis of basaltic ash from a variety of eruptive conditions: a weak ash-producing event at Etna on 11 November 2006, ash emission, paroxysmal explosions and lava-sea water interaction during the 2007 eruptive crisis of Stromboli volcano, and finally more typical Strombolian activity in 2008 at Stromboli. Etna samples were collected at eight locations between 2 and 20 km from source. Stromboli samples were collected between 28 February and 19 March 2007, and from single explosions in September 2008. A JEOL JSM 6500 Field Emission Scanning Electron Microprobe (FE-SEM) was used to image and quantify millimeter- to submicron-scale features of ash particles. Beside qualitative observation of the particles, semi-automated FE-SEM data include particle morphoscopy (area, perimeter, compactness, equivalent diameter) and surface chemistry. The morphoscopy data can be compared to grain size data collected by conventional techniques, while the surface chemistry data can be considered a proxy for component analysis, more typically performed using a binocular microscope, as it reflects the degree of crystallinity and alteration of the particles. Preliminary data indicate that insight into the particle source and eruptive dynamics of both volcanoes can be obtained from detailed analysis of the ash. In particular, the different sources of ash at Stromboli have highly distinctive alteration signatures, while the Etna samples exemplify the potential of the approach to discern subtle differences in ash particles from the same plume collected at different locations, thus outlining relatively small-scale plume zonations.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFM.V21C2010L
- Keywords:
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- 8419 VOLCANOLOGY / Volcano monitoring;
- 8428 VOLCANOLOGY / Explosive volcanism;
- 8429 VOLCANOLOGY / Lava rheology and morphology;
- 8434 VOLCANOLOGY / Magma migration and fragmentation