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Release characteristics of overpressurised gas from complex vents: implications for volcanic hazards
Many explosive volcanic eruptions produce underexpanded starting gas-particle jets. The dynamics of the accompanying pyroclast ejection can be affected by several parameters, including magma texture, gas overpressure, erupted volume and geometry. With respect to the latter, volcanic craters and vent...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Springer Berlin Heidelberg
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7532131/ https://www.ncbi.nlm.nih.gov/pubmed/33088010 http://dx.doi.org/10.1007/s00445-020-01407-2 |
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author | Schmid, Markus Kueppers, Ulrich Cigala, Valeria Sesterhenn, Jörn Dingwell, Donald B. |
author_facet | Schmid, Markus Kueppers, Ulrich Cigala, Valeria Sesterhenn, Jörn Dingwell, Donald B. |
author_sort | Schmid, Markus |
collection | PubMed |
description | Many explosive volcanic eruptions produce underexpanded starting gas-particle jets. The dynamics of the accompanying pyroclast ejection can be affected by several parameters, including magma texture, gas overpressure, erupted volume and geometry. With respect to the latter, volcanic craters and vents are often highly asymmetrical. Here, we experimentally evaluate the effect of vent asymmetry on gas expansion behaviour and gas jet dynamics directly above the vent. The vent geometries chosen for this study are based on field observations. The novel element of the vent geometry investigated herein is an inclined exit plane (5, 15, 30° slant angle) in combination with cylindrical and diverging inner geometries. In a vertical setup, these modifications yield both laterally variable spreading angles as well as a diversion of the jets, where inner geometry (cylindrical/diverging) controls the direction of the inclination. Both the spreading angle and the inclination of the jet are highly sensitive to reservoir (conduit) pressure and slant angle. Increasing starting reservoir pressure and slant angle yield (1) a maximum spreading angle (up to 62°) and (2) a maximum jet inclination for cylindrical vents (up to 13°). Our experiments thus constrain geometric contributions to the mechanisms controlling eruption jet dynamics with implications for the generation of asymmetrical distributions of proximal hazards around volcanic vents. |
format | Online Article Text |
id | pubmed-7532131 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | Springer Berlin Heidelberg |
record_format | MEDLINE/PubMed |
spelling | pubmed-75321312020-10-19 Release characteristics of overpressurised gas from complex vents: implications for volcanic hazards Schmid, Markus Kueppers, Ulrich Cigala, Valeria Sesterhenn, Jörn Dingwell, Donald B. Bull Volcanol Research Article Many explosive volcanic eruptions produce underexpanded starting gas-particle jets. The dynamics of the accompanying pyroclast ejection can be affected by several parameters, including magma texture, gas overpressure, erupted volume and geometry. With respect to the latter, volcanic craters and vents are often highly asymmetrical. Here, we experimentally evaluate the effect of vent asymmetry on gas expansion behaviour and gas jet dynamics directly above the vent. The vent geometries chosen for this study are based on field observations. The novel element of the vent geometry investigated herein is an inclined exit plane (5, 15, 30° slant angle) in combination with cylindrical and diverging inner geometries. In a vertical setup, these modifications yield both laterally variable spreading angles as well as a diversion of the jets, where inner geometry (cylindrical/diverging) controls the direction of the inclination. Both the spreading angle and the inclination of the jet are highly sensitive to reservoir (conduit) pressure and slant angle. Increasing starting reservoir pressure and slant angle yield (1) a maximum spreading angle (up to 62°) and (2) a maximum jet inclination for cylindrical vents (up to 13°). Our experiments thus constrain geometric contributions to the mechanisms controlling eruption jet dynamics with implications for the generation of asymmetrical distributions of proximal hazards around volcanic vents. Springer Berlin Heidelberg 2020-10-02 2020 /pmc/articles/PMC7532131/ /pubmed/33088010 http://dx.doi.org/10.1007/s00445-020-01407-2 Text en © The Author(s) 2020 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 licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence 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 licence, visit http://creativecommons.org/licenses/by/4.0/. |
spellingShingle | Research Article Schmid, Markus Kueppers, Ulrich Cigala, Valeria Sesterhenn, Jörn Dingwell, Donald B. Release characteristics of overpressurised gas from complex vents: implications for volcanic hazards |
title | Release characteristics of overpressurised gas from complex vents: implications for volcanic hazards |
title_full | Release characteristics of overpressurised gas from complex vents: implications for volcanic hazards |
title_fullStr | Release characteristics of overpressurised gas from complex vents: implications for volcanic hazards |
title_full_unstemmed | Release characteristics of overpressurised gas from complex vents: implications for volcanic hazards |
title_short | Release characteristics of overpressurised gas from complex vents: implications for volcanic hazards |
title_sort | release characteristics of overpressurised gas from complex vents: implications for volcanic hazards |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7532131/ https://www.ncbi.nlm.nih.gov/pubmed/33088010 http://dx.doi.org/10.1007/s00445-020-01407-2 |
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