The importance of grain size and shape in controlling the dispersion of the Vedde cryptotephra
Abstract Volcanic ash is dispersed in the atmosphere according to meteorology and particle properties, including size and shape. However, the multiple definitions of size and shape for non‐spherical particles affect our ability to use physical particle properties to understand tephra transport. More...
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crwiley:10.1002/jqs.3152 2024-06-02T08:09:05+00:00 The importance of grain size and shape in controlling the dispersion of the Vedde cryptotephra Saxby, Jennifer Rust, Alison Cashman, Katharine Beckett, Frances Kungl. Vetenskaps- och Vitterhets-Samhället i Göteborg AXA Research Fund Natural Environment Research Council Met Office Academic Partnership 2019 http://dx.doi.org/10.1002/jqs.3152 https://onlinelibrary.wiley.com/doi/pdf/10.1002/jqs.3152 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/jqs.3152 en eng Wiley http://creativecommons.org/licenses/by/4.0/ Journal of Quaternary Science volume 35, issue 1-2, page 175-185 ISSN 0267-8179 1099-1417 journal-article 2019 crwiley https://doi.org/10.1002/jqs.3152 2024-05-03T11:16:31Z Abstract Volcanic ash is dispersed in the atmosphere according to meteorology and particle properties, including size and shape. However, the multiple definitions of size and shape for non‐spherical particles affect our ability to use physical particle properties to understand tephra transport. Moreover, although particles are often excluded from operational ash dispersion model setups, ash in tephra deposits 1000 km from source can exceed . Here we measure the shape and size of samples of Vedde ash from Iceland, an exceptionally widespread tephra layer in Europe, collected in Iceland and Norway. Using X‐ray computed tomography and optical microscopy, we show that distal ash is more anisotropic than proximate ash, suggesting that shape exerts an important control on tephra dispersion. Shape also impacts particle size measurements. Particle long axis, a parameter often reported by tephrochronologists, is on average greater than geometric size, used by dispersion modellers. By using geometric size and quantifying shape, we can explain the transport of Vedde ash particles more than 1200 km from source. We define a set of best practices for measuring the size and shape of cryptotephra shards and discuss the benefits and limitations of using physical particle properties to understand cryptotephra transport. Article in Journal/Newspaper Iceland Wiley Online Library Norway Journal of Quaternary Science 35 1-2 175 185 |
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English |
description |
Abstract Volcanic ash is dispersed in the atmosphere according to meteorology and particle properties, including size and shape. However, the multiple definitions of size and shape for non‐spherical particles affect our ability to use physical particle properties to understand tephra transport. Moreover, although particles are often excluded from operational ash dispersion model setups, ash in tephra deposits 1000 km from source can exceed . Here we measure the shape and size of samples of Vedde ash from Iceland, an exceptionally widespread tephra layer in Europe, collected in Iceland and Norway. Using X‐ray computed tomography and optical microscopy, we show that distal ash is more anisotropic than proximate ash, suggesting that shape exerts an important control on tephra dispersion. Shape also impacts particle size measurements. Particle long axis, a parameter often reported by tephrochronologists, is on average greater than geometric size, used by dispersion modellers. By using geometric size and quantifying shape, we can explain the transport of Vedde ash particles more than 1200 km from source. We define a set of best practices for measuring the size and shape of cryptotephra shards and discuss the benefits and limitations of using physical particle properties to understand cryptotephra transport. |
author2 |
Kungl. Vetenskaps- och Vitterhets-Samhället i Göteborg AXA Research Fund Natural Environment Research Council Met Office Academic Partnership |
format |
Article in Journal/Newspaper |
author |
Saxby, Jennifer Rust, Alison Cashman, Katharine Beckett, Frances |
spellingShingle |
Saxby, Jennifer Rust, Alison Cashman, Katharine Beckett, Frances The importance of grain size and shape in controlling the dispersion of the Vedde cryptotephra |
author_facet |
Saxby, Jennifer Rust, Alison Cashman, Katharine Beckett, Frances |
author_sort |
Saxby, Jennifer |
title |
The importance of grain size and shape in controlling the dispersion of the Vedde cryptotephra |
title_short |
The importance of grain size and shape in controlling the dispersion of the Vedde cryptotephra |
title_full |
The importance of grain size and shape in controlling the dispersion of the Vedde cryptotephra |
title_fullStr |
The importance of grain size and shape in controlling the dispersion of the Vedde cryptotephra |
title_full_unstemmed |
The importance of grain size and shape in controlling the dispersion of the Vedde cryptotephra |
title_sort |
importance of grain size and shape in controlling the dispersion of the vedde cryptotephra |
publisher |
Wiley |
publishDate |
2019 |
url |
http://dx.doi.org/10.1002/jqs.3152 https://onlinelibrary.wiley.com/doi/pdf/10.1002/jqs.3152 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/jqs.3152 |
geographic |
Norway |
geographic_facet |
Norway |
genre |
Iceland |
genre_facet |
Iceland |
op_source |
Journal of Quaternary Science volume 35, issue 1-2, page 175-185 ISSN 0267-8179 1099-1417 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.1002/jqs.3152 |
container_title |
Journal of Quaternary Science |
container_volume |
35 |
container_issue |
1-2 |
container_start_page |
175 |
op_container_end_page |
185 |
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1800754688973340672 |