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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...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Publishing Group UK
2017
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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. |
format | Online Article Text |
id | pubmed-5686202 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | Nature Publishing Group UK |
record_format | MEDLINE/PubMed |
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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