https://dx.doi.org/10.1016/j.jvolgeores.2013.02.002">
 

3-D reconstruction of ash vesicularity: Insights into the origin of ash-rich explosive eruptions

Abstract

Explosive volcanic eruptions are characterized by highly variable degrees of magma fragmentation, even during a single eruptive event. The increasing amount of fine pyroclasts is often uncritically related to explosive magma–water interaction (i.e., hydromagmatic fragmentation). Here we report examination of two examples of major explosive eruptions from the Quaternary Vulsini Volcanic District (central Italy), in which the fine-grained nature of deposits, even in near-vent settings, indicates negligible effect of transport and implies the eruption of highly fragmented magmas. SEM morphoscopy of the juvenile products rules out extensive ash production due to hydromagmatic fragmentation. We apply a recently developed Stereo-Scanning Electron Microscopy (SSEM) technique (Proussevitch et al., 2011) to determine vesicularity features (e.g., bubble size distribution and bubble number density; hereafter BSD and BND, respectively) of ash particles. SSEM analysis provides new insights into magma vesiculation history and fragmentation mechanism leading to major ash-rich eruptions. We conclude that extensive ash production was related to essentially magmatic processes involving high degrees of decompression in shallow magma reservoirs.

Department

Earth Systems Research Center

Publication Date

4-1-2013

Journal Title

Journal of Volcanology and Geothermal Research

Publisher

Elsevier

Digital Object Identifier (DOI)

https://dx.doi.org/10.1016/j.jvolgeores.2013.02.002

Document Type

Article

Rights

Copyright © 2013 Elsevier B.V. All rights reserved.

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