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TitreCurrent deformation in the northern Canadian Cordillera inferred from GPS measurements
AuteurLeonard, L J; Hyndman, R D; Mazzotti, S; Nykolaishen, L; Schmidt, M; Hippchen, S
SourceJournal of Geophysical Research vol. 112, no. B11, B11401, 2007 p. 1-15, https://doi.org/10.1029/2007JB005061 (Accès ouvert)
Année2007
Séries alt.Secteur des sciences de la Terre, Contribution externe 20080020
ÉditeurWiley-Blackwell
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1029/2007JB005061
Mediapapier; en ligne; numérique
Formatspdf
ProvinceYukon; Territoires du Nord-Ouest; Colombie-Britannique; Région extracotière de l'ouest; Région extracotière du nord
SNRC94; 95; 96; 97; 104; 105; 106; 107; 114; 115; 116; 117
Lat/Long OENS-144.0000 -120.0000 72.0000 56.0000
Sujetscadre tectonique; vitesse des ondes sismiques; sismicité; secousses séismiques; tectonique de plaques; marges plaques; marges continentales; déformation; orogenèse; caractéristiques structurales; plis; failles, chevauchement; failles, décrochement; lithosphère; mouvements de la croûte; épaisseur de la croûte; raccourcissement de la croûte; soulèvement de la croûte; déplacement; Cordillère; Terrane d'Yakutat ; Craton de l'Américque du Nord; Bloc d'Yakutat ; Faille de Fairweather ; Système de failles de Chugach - St. Elias ; Faille de Denali ; tectonique; géophysique
Illustrationssketch maps; plots; tables
Diffusé2007 11 03
Résumé(disponible en anglais seulement)
Continuous and campaign-style Global Positioning System (GPS) measurements provide new constraints on the first-order current deformation pattern of the northern Cordillera of NW Canada and eastern Alaska. The Yakutat block is currently colliding with North America in the corner of the Gulf of Alaska. Our data infer that relative Yakutat - North America motion is accommodated across the eastern boundary by rightlateral motion (~40 mm/a), mainly on the Fairweather fault, and minor shortening (~6 mm/a). To the north, collision is taken up by shortening (~31 mm/a) mainly on the Chugach - St. Elias fault system, with westward extrusion and possible counterclockwise rotation of the Yakutat block and Alaskan fore arc facilitated by ~23 mm/a right-lateral motion that is shared by several faults. The seismicity pattern indicates that plate boundary deformation is far reaching, producing strain throughout eastern Alaska,Yukon, and western Northwest Territories. Our GPS data confirm the transfer of strain from the Yakutat collision zone and enable the extent of plate boundary deformation to be mapped, thereby defining the western edge of "stable" North America. GPS sites in SW Yukon show motion of 3 - 10 mm/a to the NE, confirming that strain is transferred at least 400 km from the Yakutat collision. Continued transfer north toward the Mackenzie Delta and NE to the Mackenzie Mountains, indicated by current seismicity, is not yet well resolved by the campaign GPS data, which are hampered by coseismic and postseismic effects of the 2002 Mw 7.9 earthquake on the Denali fault in eastern Alaska.
GEOSCAN ID225059