| Titre | Tectonics, dynamics, and seismic hazard in the Canada-Alaska Cordillera |
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| Auteur | Mazzotti, S ;
Leonard, L J; Hyndman, R D; Cassidy, J F |
| Source | Active tectonics and seismic potential of Alaska; American Geophysical Union Geophysical Monograph no. 179, 2008 p. 297-319, https://doi.org/10.1029/179GM17 |
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| Année | 2008 |
| Séries alt. | Secteur des sciences de la Terre, Contribution externe 20070423 |
| Éditeur | American Geophysical Union |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1029/179GM17 |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Province | Yukon; Colombie-Britannique |
| SNRC | 92; 93; 94; 95; 102; 103; 104; 105; 106; 107; 114; 115; 116; 117 |
| Région | Alaska; Cordillera; Queen Charlotte |
| Lat/Long OENS | -144.0000 -118.0000 72.0000 46.0000 |
| Sujets | risque sismique; sismicité; zones sismiques; interprétations tectoniques; milieux tectoniques; tectonique de plaques; modèles tectoniques; frontières de plaques; subduction; secousses séismiques; risque
de tremblement de terre; études séismiques; mécanismes de tremblement de terre; déformation; dangers pour la santé; tectonique; géologie de l'environnement; géophysique |
| Illustrations | cartes de localisation; tableaux; coupes transversales |
| Programme | Réduction des risques dus aux aléas naturels |
| Diffusé | 2013 03 19 |
| Résumé | (disponible en anglais seulement)
The North America Cordillera mobile belt has accommodated relative motion between the North America plate and various oceanic plates since the early Mesozoic.
The northern half of the Cordillera (Canada - Alaska Cordillera) extends from northern Washington through western Canada and central Alaska and can be divided into four tectonic domains associated with different plate boundary interactions, variable
seismicity, and seismic hazard. We present a quantitative tectonic model of the Canada - Alaska Cordillera based on an integrated set of seismicity and GPS data for these four domains: south (Cascadia subduction region), central (Queen Charlotte -
Fairweather transcurrent region), north (Yakutat collision region), and Alaska (Alaska subduction region). This tectonic model is compared with a dynamic model that accounts for lithosphere strength contrasts and internal/boundary force balance. We
argue that most of the Canada - Alaska Cordillera is an orogenic float where current tectonics are mainly limited to the upper crust, which is mechanically decoupled from the lower part of the lithosphere. Variations in deformation style and
magnitude across the Cordillera are mostly controlled by the balance between plate boundary forces and topography-related gravitational forces.
In particular, the strong compression and gravitational forces associated with the Yakutat collision
zone are the primary driver of the complex tectonics from eastern Yukon to central Alaska, resulting in crustal extrusion, translation, and deformation across a 1500 ´ 1000-km2 region. This tectonic - dynamic model can be used to provide quantitative
constraints to seismic hazard models. We present a simple example of mapping Mw = 7 earthquake return periods throughout the Cordillera. |
| GEOSCAN ID | 224513 |
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