Slope Evolution and the Accommodation of Oblique Convergence From the Central to the Northern Queen Charlotte Fault
Description:
The Queen Charlotte Fault (QCF), the transform boundary between the Pacific and North American tectonic plates offshore Vancouver and southeastern Alaska, experiences rapid deformation at approximately 55 mm/year. This makes it one of the fastest-slipping continental-oceanic transform systems globally. Transpressional deformation, which occurs along the fault, is controlled by variations in fault strike with respect to plate motion leading to increasing degrees of convergence along strike from north to south. The Transform Obliquity on the Queen Charlotte Fault and Earthquake Study (TOQUES) gathered new multichannel seismic reflection data along a ~450 km fault section in 2021. This work focuses on the northern segment, near the site of the 2013 Mw 7.5 Craig, Alaska earthquake. Aftershock sequences suggest that the main QCF dips eastwards or active fault strands exist within the North American plate. We present seismic profiles crossing the 2013 epicentral region, examining fault zone architecture, crustal deformation mechanisms, and deep structural relationships. The profiles reveal a series of normal faults within the Pacific crust, a slightly eastward dipping Pacific basement, and sediments containing multiple vertical faults at the base of the continental slope. The main QCF trace is located on the continental slope. Mid-slope basins record several deformation stages and host multiple vertical faults. On the North American continental shelf, we see glacially truncated, east-dipping strata and minor seafloor sediment deformation. Our observations suggest that strike-slip deformation may be distributed across multiple structures.
Session: Structure, Seismicity and Dynamics of the Queen Charlotte-Fairweather Fault System - I
Type: Oral
Date: 5/1/2024
Presentation Time: 05:15 PM (local time)
Presenting Author: Olumide
Student Presenter: Yes
Invited Presentation:
Authors
Olumide Adedeji Presenting Author Corresponding Author adeolumideji@gmail.com University of New Mexico |
Lindsay Worthington lworthington@unm.edu University of New Mexico |
Collin Brandl cbrandl@unm.edu University of New Mexico |
Maureen Walton maureen.walton@nrlssc.navy.mil U.S. Naval Research Laboratory |
Emily Roland rolande2@wwu.edu Western Washington University |
Lazaro Garza garzal2@wwu.edu Western Washington University |
Andrew Gase gasea@wwu.edu Western Washington University |
Mladen Nedimović mladen@dal.ca Dalhousie University |
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Slope Evolution and the Accommodation of Oblique Convergence From the Central to the Northern Queen Charlotte Fault
Category
Structure, Seismicity and Dynamics of the Queen Charlotte-Fairweather Fault System