Geometry, kinematics, and Quaternary activity of the brittle Leech River fault zone, southern Vancouver Island, British Columbia, Canada

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dc.contributor.author Graham, Audrey
dc.date.accessioned 2018-02-06T15:53:43Z
dc.date.copyright 2018 en_US
dc.date.issued 2018-02-06
dc.identifier.uri https://dspace.library.uvic.ca//handle/1828/9047
dc.description.abstract Southern Vancouver Island lies on the forearc of the Cascadia subduction zone, north of a concave bend in the plate boundary centred around the Olympic Mountains. The bend in the margin coincides with a significant decrease in northward-directed trench-parallel forearc migration, and a network of active crustal faults in the Puget Lowland east of the Olympic Mountains accommodates permanent north-south shortening and transpression. The nature of forearc deformation on southern Vancouver Island is less well constrained, due in part to the unknown extent and kinematics of active crustal faulting. Recent work has shown that a brittle fault zone associated with the Eocene terrane-bounding Leech River fault has produced at least two surface-rupturing earthquakes in the late Quaternary. I use LiDAR-derived topographic data, slip-sense indicator analysis of slickenlines on fault planes, electrical resistivity tomography (ERT), and ground-penetrating radar (GPR) to investigate the geometry, kinematics, and Quaternary activity along the eastern half of the active, brittle Leech River fault zone. My mapping reveals a complex, near-vertical zone up to 1 km wide and 25 km long that exhibits many characteristics of a strike-slip fault. Displaced Quaternary deposits are observed directly at two sites in the western 8 km of the study area, and inferred through geophysical imagery, topographic data, and liquefaction features to extend to the eastern terrestrial extent of the fault zone towards previously mapped active faults in the Juan de Fuca Strait and the Darrington-Devil’s Mountain fault zone in western Washington. I use fault kinematics and geometry to show that the eastern Leech River fault zone has been reactivated as a right-lateral strike-slip fault that accommodates forearc deformation within the modern stress field north of the Olympic Mountains. en_US
dc.language English eng
dc.language.iso en en_US
dc.rights Available to the World Wide Web en_US
dc.subject neotectonics en_US
dc.subject active crustal faults en_US
dc.subject forearc deformation en_US
dc.subject GPR en_US
dc.subject electrical resistivity en_US
dc.subject slip-sense analysis en_US
dc.subject LiDAR en_US
dc.subject tectonic geomorphology en_US
dc.subject Cascadia subduction zone en_US
dc.title Geometry, kinematics, and Quaternary activity of the brittle Leech River fault zone, southern Vancouver Island, British Columbia, Canada en_US
dc.type Thesis en_US
dc.contributor.supervisor Morell, Kristin
dc.contributor.supervisor Levson, Victor M. (Victor Mathew)
dc.degree.department School of Earth and Ocean Sciences en_US
dc.degree.level Master of Science M.Sc. en_US
dc.description.scholarlevel Graduate en_US
dc.description.embargo 2018-12-01

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