Collaborative Research: Permanent forearc strain partitioning in Northern Cascadia

Northern Arizona University, Flagstaff AZ

Investigators

Abstract

This work provides the first detailed characterization of the behavior of past earthquakes that have occurred on active, on-land, shallow faults in southern British Columbia, Canada. The research has important societal benefits that include providing key inputs needed for seismic hazard assessment in populated areas of Vancouver Island, British Columbia and northwestern Washington, USA. These types of data are necessary to help inform the development of public policy that can reduce the loss of life and property due to future earthquakes. Other important societal outcomes include contributions to STEM (science, technology, engineering and mathematics) education and the development of a diverse globally competitive STEM workforce by providing support for the training of graduate and undergraduate students. The project also supports the research of two female, early career scientists, and facilitates international collaborations between industry partners, policy makers, scientists and students. This project is evaluating the role of slab geometry and oblique convergence in the generation of forearc deformation in northern Cascadia by determining fault kinematics and the Holocene slip history of three prominent faults on Vancouver Island, British Columbia, Canada. Using a combination of bedrock mapping and structural analysis, surficial mapping of offset Quaternary deposits, and exploratory paleoseismic trenches, the research is testing the hypothesis that newly identified active crustal faults contribute to active oroclinal bending in response to the component of relative plate motion parallel to the strike of the slab. This work provides the first documentation of Quaternary activity on a set of faults previously thought to be last active in the Eocene, and provides fundamental kinematic and slip history data necessary to test models of plate boundary strain partitioning. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.