| Titre | Deformation rates estimated from earthquakes in the northern Cordillera of Canada and eastern Alaska |
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| Auteur | Leonard, L J; Mazzotti, S ; Hyndman, R D |
| Source | Journal of Geophysical Research vol. 113, B08406, 2008, 18p., https://doi.org/10.1029/2007JB005456  Accès ouvert |
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| Année | 2008 |
| Séries alt. | Secteur des sciences de la Terre, Contribution externe 20080060 |
| Éditeur | Wiley-Blackwell |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1029/2007JB005456 |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Province | Colombie-Britannique; Yukon; Territoires du Nord-Ouest |
| SNRC | 94; 95; 96; 97A; 97B; 97C; 97D; 104; 105; 106; 107; 114; 115; 116; 117 |
| Région | Cordillera; Alaska |
| Lat/Long OENS | -160.0000 -120.0000 71.0000 56.0000 |
| Sujets | secousses séismiques; études séismiques; risque de tremblement de terre; magnitudes des séismes; mécanismes de tremblement de terre; catalogues des tremblements de terre; déformation; tectonique de
plaques; milieux tectoniques; interprétations tectoniques; sismicité; Bloc d'Yakutat ; Système de failles de Denali ; Faille de Fairweather ; Faille de Tintina ; Poussée de Dawson ; géophysique; géologie structurale |
| Illustrations | cartes de localisation |
| Programme | Réduction des risques dus aux aléas naturels |
| Diffusé | 2008 08 13 |
| Résumé | (disponible en anglais seulement)
We estimate deformation rates from earthquake catalog statistics to investigate current strain distribution resulting from the collision of the Yakutat block
with North America. The collision is accommodated over a broad region of Alaska and NW Canada in a variety of tectonic regimes. Our estimates have significant uncertainties, but the results are generally in agreement with other deformation rate
estimates (GPS and geological data) and provide useful first-order constraints on local long-term tectonic deformation and seismic hazard. We estimate that 50-75% of relative plate motion is taken up by earthquakes on the Yakutat/North America
boundaries, with lateral crustal extrusion, other far-field strain, and possibly aseismic creep accommodating the remainder. We calculate dextral strike slip of 4.5-10.2 mm/a on the Denali fault system in Alaska, remarkably similar to late
Pleistocene/Holocene rates from geomorphic offsets. Right-lateral motion essentially bypasses the Denali fault in easternmost Alaska and westernmost Yukon, passing instead along the Totschunda and Duke River fault systems. Right-lateral transpression
of 5-10 mm/a suggests that the Alaskan fore arc does not have fully block-like behavior. Between the Denali and Tintina-Kaltag faults in Alaska, 10-20 mm/a of deformation is shared by several NE trending "bookshelf" faults that accommodate dextral
shear. Significant seismic deformation (in cases higher than expected from GPS data) is indicated in the NE Cordillera, where pre-existing faults have a strong control on the pattern and mechanisms of current deformation. |
| GEOSCAN ID | 225102 |
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