An Updated Velocity Field for Northern Canadian Cordillera

Abstract:

The Mackenzie Mountains, located in the Yukon and Northwest territories of Canada, mark the northern extent of North American Cordillera. The regional tectonic character is the result of Yakutat collision along the southern margin of Alaska and subsequent thrusting and right-lateral strain accommodation along major regional structures such as the Denali/Fairweather and Tintina faults. Geophysical deployments in the region have been relatively sparse until recently, with a temporary array of seismic stations bolstering the Alaska deployment of the Earthscope Transportable array and the installation of several continuous GPS sites leading to a wealth of new data with the potential to address important outstanding questions. In this study, we examine surface velocities fit to ~15 years of repeat GPS measurements in order to highlight some trends in elastic deformation. We apply updated corrections for regional postglacial trends and the 2002 M 7.9 Denali Fault earthquake in order to present a new secular velocity field for the region and compare these results with estimates for deformation gathered from earthquake catalogue statistics. Our results shed light on the spatial extent of tectonic deformation into the North American continental interior as well as the role of regional structures in accommodating far field forces.