| Titre | Mechanical and hydrological effects of seamount subduction on megathrust stress and slip |
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| Auteur | Sun, T ; Saffer,
D; Ellis, S |
| Source | Nature Geoscience vol. 13, 2020 p. 249-255, https://doi.org/10.1038/s41561-020-0542-0 |
| Liens | Erratum
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| Image |  |
| Année | 2020 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20190610 |
| Éditeur | Springer Nature |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1038/s41561-020-0542-0 |
| Media | papier; en ligne; numérique |
| Formats | pdf; html |
| Sujets | tectonique de plaques; zones de subduction; secousses séismiques; sismicité; mouvements des plaques; caractéristiques sous-marines; monts sous-marins; topographie du fond océanique; détermination des
contraintes; fluage; evolution de la croûte; structure de la croûte; déformation; formation de failles; pressions interstitielles; modèles; drainage; porosité; déformation; géologie marine; tectonique; hydrogéologie; géologie structurale;
sédimentologie; Nature et environnement; Sciences et technologie |
| Illustrations | modèles; profils; graphiques; cartes de localisation; cartes géolscientiques généralisées; coupes schématiques transversales; diagrammes; tableaux |
| Diffusé | 2020 03 02; 2020 03 16 |
| Résumé | (disponible en anglais seulement)
Subduction of rough seafloor and seamounts is thought to impact a broad range of geodynamic processes, including megathrust slip behaviour, forearc fluid flow
and long-term structural evolution in the overriding plate. Although there are many conceptual models describing the effects of seamount subduction, our quantitative and mechanistic understanding of the underlying deformation and fluid processes
remains incomplete. Here we investigate the interplay between sediment consolidation, faulting and the evolution of stress and pore fluid pressure in response to seamount subduction, using a numerical model that couples mechanical and hydrological
processes and is constrained by laboratory and field observations. Our results show that subducting topography drives marked spatial variations in tectonic loading, sediment consolidation and megathrust stress state. Downdip of a subducting seamount
on its leading flank, enhanced compression and drainage lead to large fault-normal stress and overconsolidated wall rocks. A stress shadow in the seamount's wake leads to anomalously high sediment porosity. These variations help explain observed
patterns of megathrust slip, with earthquakes and microseismicity favoured at the downdip edge of seamounts and aseismic or slow slip in the updip stress shadow. |
| GEOSCAN ID | 322176 |
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