Damage amplification during repetitive seismic waves in mechanically loaded rocks
Cycles of stress build-up and release are inherent to tectonically active planets. Such stress oscillations impart strain and damage, prompting mechanically loaded rocks and materials to fail. Here, we investigate, under uniaxial conditions, damage accumulation and weakening caused by time-dependent...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Nature Publishing Group UK
2023
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9870869/ https://www.ncbi.nlm.nih.gov/pubmed/36690640 http://dx.doi.org/10.1038/s41598-022-26721-x |
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author | Lamur, Anthony Kendrick, Jackie E. Schaefer, Lauren N. Lavallée, Yan Kennedy, Ben M. |
author_facet | Lamur, Anthony Kendrick, Jackie E. Schaefer, Lauren N. Lavallée, Yan Kennedy, Ben M. |
author_sort | Lamur, Anthony |
collection | PubMed |
description | Cycles of stress build-up and release are inherent to tectonically active planets. Such stress oscillations impart strain and damage, prompting mechanically loaded rocks and materials to fail. Here, we investigate, under uniaxial conditions, damage accumulation and weakening caused by time-dependent creep (at 60, 65, and 70% of the rocks’ expected failure stress) and repeating stress oscillations (of ± 2.5, 5.0 or 7.5% of the creep load), simulating earthquakes at a shaking frequency of ~ 1.3 Hz in volcanic rocks. The results show that stress oscillations impart more damage than constant loads, occasionally prompting sample failure. The magnitudes of the creep stresses and stress oscillations correlate with the mechanical responses of our porphyritic andesites, implicating progressive microcracking as the cause of permanent inelastic strain. Microstructural investigation reveals longer fractures and higher fracture density in the post-experimental rock. We deconvolve the inelastic strain signal caused by creep deformation to quantify the amount of damage imparted by each individual oscillation event, showing that the magnitude of strain is generally largest with the first few oscillations; in instances where pre-existing damage and/or the oscillations’ amplitude favour the coalescence of micro-cracks towards system scale failure, the strain signal recorded shows a sharp increase as the number of oscillations increases, regardless of the creep condition. We conclude that repetitive stress oscillations during earthquakes can amplify the amount of damage in otherwise mechanically loaded materials, thus accentuating their weakening, a process that may affect natural or engineered structures. We specifically discuss volcanic scenarios without wholesale failure, where stress oscillations may generate damage, which could, for example, alter pore fluid pathways, modify stress distribution and affect future vulnerability to rupture and associated hazards. |
format | Online Article Text |
id | pubmed-9870869 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2023 |
publisher | Nature Publishing Group UK |
record_format | MEDLINE/PubMed |
spelling | pubmed-98708692023-01-25 Damage amplification during repetitive seismic waves in mechanically loaded rocks Lamur, Anthony Kendrick, Jackie E. Schaefer, Lauren N. Lavallée, Yan Kennedy, Ben M. Sci Rep Article Cycles of stress build-up and release are inherent to tectonically active planets. Such stress oscillations impart strain and damage, prompting mechanically loaded rocks and materials to fail. Here, we investigate, under uniaxial conditions, damage accumulation and weakening caused by time-dependent creep (at 60, 65, and 70% of the rocks’ expected failure stress) and repeating stress oscillations (of ± 2.5, 5.0 or 7.5% of the creep load), simulating earthquakes at a shaking frequency of ~ 1.3 Hz in volcanic rocks. The results show that stress oscillations impart more damage than constant loads, occasionally prompting sample failure. The magnitudes of the creep stresses and stress oscillations correlate with the mechanical responses of our porphyritic andesites, implicating progressive microcracking as the cause of permanent inelastic strain. Microstructural investigation reveals longer fractures and higher fracture density in the post-experimental rock. We deconvolve the inelastic strain signal caused by creep deformation to quantify the amount of damage imparted by each individual oscillation event, showing that the magnitude of strain is generally largest with the first few oscillations; in instances where pre-existing damage and/or the oscillations’ amplitude favour the coalescence of micro-cracks towards system scale failure, the strain signal recorded shows a sharp increase as the number of oscillations increases, regardless of the creep condition. We conclude that repetitive stress oscillations during earthquakes can amplify the amount of damage in otherwise mechanically loaded materials, thus accentuating their weakening, a process that may affect natural or engineered structures. We specifically discuss volcanic scenarios without wholesale failure, where stress oscillations may generate damage, which could, for example, alter pore fluid pathways, modify stress distribution and affect future vulnerability to rupture and associated hazards. Nature Publishing Group UK 2023-01-23 /pmc/articles/PMC9870869/ /pubmed/36690640 http://dx.doi.org/10.1038/s41598-022-26721-x Text en © The Author(s) 2023 https://creativecommons.org/licenses/by/4.0/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/ (https://creativecommons.org/licenses/by/4.0/) . |
spellingShingle | Article Lamur, Anthony Kendrick, Jackie E. Schaefer, Lauren N. Lavallée, Yan Kennedy, Ben M. Damage amplification during repetitive seismic waves in mechanically loaded rocks |
title | Damage amplification during repetitive seismic waves in mechanically loaded rocks |
title_full | Damage amplification during repetitive seismic waves in mechanically loaded rocks |
title_fullStr | Damage amplification during repetitive seismic waves in mechanically loaded rocks |
title_full_unstemmed | Damage amplification during repetitive seismic waves in mechanically loaded rocks |
title_short | Damage amplification during repetitive seismic waves in mechanically loaded rocks |
title_sort | damage amplification during repetitive seismic waves in mechanically loaded rocks |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9870869/ https://www.ncbi.nlm.nih.gov/pubmed/36690640 http://dx.doi.org/10.1038/s41598-022-26721-x |
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