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The Elusive Evidence of Volcanic Lightning

Lightning strikes are known to morphologically alter and chemically reduce geologic formations and deposits, forming fulgurites. A similar process occurs as the result of volcanic lightning discharge, when airborne volcanic ash is transformed into lightning-induced volcanic spherules (LIVS). Here, w...

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Autores principales: Genareau, K., Gharghabi, P., Gafford, J., Mazzola, M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5686202/
https://www.ncbi.nlm.nih.gov/pubmed/29138444
http://dx.doi.org/10.1038/s41598-017-15643-8
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author Genareau, K.
Gharghabi, P.
Gafford, J.
Mazzola, M.
author_facet Genareau, K.
Gharghabi, P.
Gafford, J.
Mazzola, M.
author_sort Genareau, K.
collection PubMed
description Lightning strikes are known to morphologically alter and chemically reduce geologic formations and deposits, forming fulgurites. A similar process occurs as the result of volcanic lightning discharge, when airborne volcanic ash is transformed into lightning-induced volcanic spherules (LIVS). Here, we adapt the calculations used in previous studies of lightning-induced damage to infrastructure materials to determine the effects on pseudo-ash samples of simplified composition. Using laboratory high-current impulse experiments, this research shows that within the lightning discharge channel there is an ideal melting zone that represents roughly 10% or less of the total channel radius at which temperatures are sufficient to melt the ash, regardless of peak current. The melted ash is simultaneously expelled from the channel by the heated, expanding air, permitting particles to cool during atmospheric transport before coming to rest in ash fall deposits. The limited size of this ideal melting zone explains the low number of LIVS typically observed in volcanic ash despite the frequent occurrence of lightning during explosive eruptions.
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spelling pubmed-56862022017-11-21 The Elusive Evidence of Volcanic Lightning Genareau, K. Gharghabi, P. Gafford, J. Mazzola, M. Sci Rep Article Lightning strikes are known to morphologically alter and chemically reduce geologic formations and deposits, forming fulgurites. A similar process occurs as the result of volcanic lightning discharge, when airborne volcanic ash is transformed into lightning-induced volcanic spherules (LIVS). Here, we adapt the calculations used in previous studies of lightning-induced damage to infrastructure materials to determine the effects on pseudo-ash samples of simplified composition. Using laboratory high-current impulse experiments, this research shows that within the lightning discharge channel there is an ideal melting zone that represents roughly 10% or less of the total channel radius at which temperatures are sufficient to melt the ash, regardless of peak current. The melted ash is simultaneously expelled from the channel by the heated, expanding air, permitting particles to cool during atmospheric transport before coming to rest in ash fall deposits. The limited size of this ideal melting zone explains the low number of LIVS typically observed in volcanic ash despite the frequent occurrence of lightning during explosive eruptions. Nature Publishing Group UK 2017-11-14 /pmc/articles/PMC5686202/ /pubmed/29138444 http://dx.doi.org/10.1038/s41598-017-15643-8 Text en © The Author(s) 2017 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Genareau, K.
Gharghabi, P.
Gafford, J.
Mazzola, M.
The Elusive Evidence of Volcanic Lightning
title The Elusive Evidence of Volcanic Lightning
title_full The Elusive Evidence of Volcanic Lightning
title_fullStr The Elusive Evidence of Volcanic Lightning
title_full_unstemmed The Elusive Evidence of Volcanic Lightning
title_short The Elusive Evidence of Volcanic Lightning
title_sort elusive evidence of volcanic lightning
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5686202/
https://www.ncbi.nlm.nih.gov/pubmed/29138444
http://dx.doi.org/10.1038/s41598-017-15643-8
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