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Dynamic weakening during earthquakes controlled by fluid thermodynamics
Earthquakes result from weakening of faults (transient decrease in friction) during co-seismic slip. Dry faults weaken due to degradation of fault asperities by frictional heating (e.g. flash heating). In the presence of fluids, theoretical models predict faults to weaken by thermal pressurization o...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Publishing Group UK
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6079085/ https://www.ncbi.nlm.nih.gov/pubmed/30082789 http://dx.doi.org/10.1038/s41467-018-05603-9 |
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author | Acosta, M. Passelègue, F. X. Schubnel, A. Violay, M. |
author_facet | Acosta, M. Passelègue, F. X. Schubnel, A. Violay, M. |
author_sort | Acosta, M. |
collection | PubMed |
description | Earthquakes result from weakening of faults (transient decrease in friction) during co-seismic slip. Dry faults weaken due to degradation of fault asperities by frictional heating (e.g. flash heating). In the presence of fluids, theoretical models predict faults to weaken by thermal pressurization of fault fluid. However, experimental evidence of rock/fluid interactions during dynamic rupture under realistic stress conditions remains poorly documented. Here we demonstrate that the relative contribution of thermal pressurization and flash heating to fault weakening depends on fluid thermodynamic properties. Our dynamic records of laboratory earthquakes demonstrate that flash heating drives strength loss under dry and low (1 MPa) fluid pressure conditions. Conversely, flash heating is inhibited at high fluid pressure (25 MPa) because water’s liquid–supercritical phase transition buffers frictional heat. Our results are supported by flash-heating theory modified for pressurized fluids and by numerical modelling of thermal pressurization. The heat buffer effect has maximum efficiency at mid-crustal depths (~2–5 km), where many anthropogenic earthquakes nucleate. |
format | Online Article Text |
id | pubmed-6079085 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | Nature Publishing Group UK |
record_format | MEDLINE/PubMed |
spelling | pubmed-60790852018-08-08 Dynamic weakening during earthquakes controlled by fluid thermodynamics Acosta, M. Passelègue, F. X. Schubnel, A. Violay, M. Nat Commun Article Earthquakes result from weakening of faults (transient decrease in friction) during co-seismic slip. Dry faults weaken due to degradation of fault asperities by frictional heating (e.g. flash heating). In the presence of fluids, theoretical models predict faults to weaken by thermal pressurization of fault fluid. However, experimental evidence of rock/fluid interactions during dynamic rupture under realistic stress conditions remains poorly documented. Here we demonstrate that the relative contribution of thermal pressurization and flash heating to fault weakening depends on fluid thermodynamic properties. Our dynamic records of laboratory earthquakes demonstrate that flash heating drives strength loss under dry and low (1 MPa) fluid pressure conditions. Conversely, flash heating is inhibited at high fluid pressure (25 MPa) because water’s liquid–supercritical phase transition buffers frictional heat. Our results are supported by flash-heating theory modified for pressurized fluids and by numerical modelling of thermal pressurization. The heat buffer effect has maximum efficiency at mid-crustal depths (~2–5 km), where many anthropogenic earthquakes nucleate. Nature Publishing Group UK 2018-08-06 /pmc/articles/PMC6079085/ /pubmed/30082789 http://dx.doi.org/10.1038/s41467-018-05603-9 Text en © The Author(s) 2018 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 Acosta, M. Passelègue, F. X. Schubnel, A. Violay, M. Dynamic weakening during earthquakes controlled by fluid thermodynamics |
title | Dynamic weakening during earthquakes controlled by fluid thermodynamics |
title_full | Dynamic weakening during earthquakes controlled by fluid thermodynamics |
title_fullStr | Dynamic weakening during earthquakes controlled by fluid thermodynamics |
title_full_unstemmed | Dynamic weakening during earthquakes controlled by fluid thermodynamics |
title_short | Dynamic weakening during earthquakes controlled by fluid thermodynamics |
title_sort | dynamic weakening during earthquakes controlled by fluid thermodynamics |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6079085/ https://www.ncbi.nlm.nih.gov/pubmed/30082789 http://dx.doi.org/10.1038/s41467-018-05603-9 |
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