Stress variations and non-shear earthquakes before the 2021 Iceland eruption trace magmatic fluid flow
Abstract The 2021 Fagradalsfjall eruption on Iceland’s Reykjanes Peninsula was preceded by an intense seismic swarm, offering an opportunity to investigate fluid dynamics and faulting processes at divergent plate boundary. Here we analysed 1306 full moment tensors of pre-eruption dike-related earthq...
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2025-07-01
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| Series: | Communications Earth & Environment |
| Online Access: | https://doi.org/10.1038/s43247-025-02533-5 |
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| author | Pavla Hrubcová Václav Vavryčuk Tomáš Fischer Jana Doubravová |
| author_facet | Pavla Hrubcová Václav Vavryčuk Tomáš Fischer Jana Doubravová |
| author_sort | Pavla Hrubcová |
| collection | DOAJ |
| description | Abstract The 2021 Fagradalsfjall eruption on Iceland’s Reykjanes Peninsula was preceded by an intense seismic swarm, offering an opportunity to investigate fluid dynamics and faulting processes at divergent plate boundary. Here we analysed 1306 full moment tensors of pre-eruption dike-related earthquakes and identified three faulting regimes: strike-slip, normal and reverse, driven by variations in vertical stress and controlled by fluid dynamics and crustal heterogeneity. Systematic volumetric components of these earthquakes revealed both tensile opening and compressive closing of cracks. Notably, crack closing dominated shallow, fractured crust, associated with surface subsidence above the dike, while crack opening occurred within the impermeable crust, suggesting overpressured fluids trapped at structural barriers. These variations highlight the role of fluid-rock interactions and anisotropic permeability in driving fault behaviour. Our results demonstrate that non-double-couple components of earthquakes are sensitive indicators of evolving stress and fluid migration. They provide insights into the mechanics of seismo-volcanic unrest at the slow-spreading rift. |
| format | Article |
| id | doaj-art-1ca4204b40584e5ebdab09fb313eccbe |
| institution | Kabale University |
| issn | 2662-4435 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Communications Earth & Environment |
| spelling | doaj-art-1ca4204b40584e5ebdab09fb313eccbe2025-08-20T04:02:50ZengNature PortfolioCommunications Earth & Environment2662-44352025-07-016111110.1038/s43247-025-02533-5Stress variations and non-shear earthquakes before the 2021 Iceland eruption trace magmatic fluid flowPavla Hrubcová0Václav Vavryčuk1Tomáš Fischer2Jana Doubravová3Institute of Geophysics, Czech Academy of SciencesInstitute of Geophysics, Czech Academy of SciencesFaculty of Science, Charles UniversityInstitute of Geophysics, Czech Academy of SciencesAbstract The 2021 Fagradalsfjall eruption on Iceland’s Reykjanes Peninsula was preceded by an intense seismic swarm, offering an opportunity to investigate fluid dynamics and faulting processes at divergent plate boundary. Here we analysed 1306 full moment tensors of pre-eruption dike-related earthquakes and identified three faulting regimes: strike-slip, normal and reverse, driven by variations in vertical stress and controlled by fluid dynamics and crustal heterogeneity. Systematic volumetric components of these earthquakes revealed both tensile opening and compressive closing of cracks. Notably, crack closing dominated shallow, fractured crust, associated with surface subsidence above the dike, while crack opening occurred within the impermeable crust, suggesting overpressured fluids trapped at structural barriers. These variations highlight the role of fluid-rock interactions and anisotropic permeability in driving fault behaviour. Our results demonstrate that non-double-couple components of earthquakes are sensitive indicators of evolving stress and fluid migration. They provide insights into the mechanics of seismo-volcanic unrest at the slow-spreading rift.https://doi.org/10.1038/s43247-025-02533-5 |
| spellingShingle | Pavla Hrubcová Václav Vavryčuk Tomáš Fischer Jana Doubravová Stress variations and non-shear earthquakes before the 2021 Iceland eruption trace magmatic fluid flow Communications Earth & Environment |
| title | Stress variations and non-shear earthquakes before the 2021 Iceland eruption trace magmatic fluid flow |
| title_full | Stress variations and non-shear earthquakes before the 2021 Iceland eruption trace magmatic fluid flow |
| title_fullStr | Stress variations and non-shear earthquakes before the 2021 Iceland eruption trace magmatic fluid flow |
| title_full_unstemmed | Stress variations and non-shear earthquakes before the 2021 Iceland eruption trace magmatic fluid flow |
| title_short | Stress variations and non-shear earthquakes before the 2021 Iceland eruption trace magmatic fluid flow |
| title_sort | stress variations and non shear earthquakes before the 2021 iceland eruption trace magmatic fluid flow |
| url | https://doi.org/10.1038/s43247-025-02533-5 |
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