Paleoseismic study of the XEOLXELEK–Elk Lake fault: A newly identified Holocene fault in thenorthern Cascadia forearc near Victoria, British Columbia, Canada

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Abstract

High-resolution topographic data show a tectonic scarp formed in Quaternary sediments near the city of Victoria in the northern Cascadia forearc on Vancouver Island, British Columbia, Canada. A paleoseismic trench excavation across the structure, the XEOLXELEK–Elk Lake fault, shows evidence for a Holocene (after 12.2 cal ka BP) surface-rupturing reverse-slip earthquake that produced a fault-propagation fold and resulted in the formation of a ∼1.4 to 3.5 m-high scarp. Fault-propagation fold modelling indicates ∼3.2 m of reverse slip on a 50°-dipping fault plane reproduces the observed deformation, and fault-scaling relations suggest a single earthquake rupture with this surface displacement could occur during a ∼Mw 6.1– 7.6 earthquake. Given the fault’s location within the metropolitan area of Victoria, an earthquake near this magnitude would result in significant damage to local infrastructure and this fault is worth considering in future seismic hazard assessments.
Publication type Conference Paper
Publication Subtype Conference Paper
Title Paleoseismic study of the XEOLXELEK–Elk Lake fault: A newly identified Holocene fault in thenorthern Cascadia forearc near Victoria, British Columbia, Canada
Year Published 2022
Language English
Publisher Zenodo
Contributing office(s) Geology, Minerals, Energy, and Geophysics Science Center
Description 4 p.
Larger Work Type Book
Larger Work Subtype Conference publication
Larger Work Title Proceedings of the 11th International INQUA Workshop on Paleoseismology, Active Tectonics and Archaeoseismology
First page 90
Last page 93
Conference Title 11th International INQUA Meeting on Paleoseismology, Active Tectonics and Archeoseismology
Conference Location France
Conference Date September 25-30, 2022
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