Onshore-offshore broadband seismic studies of Earth structure and tectonic processes

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My research program focuses on two main scientific objectives: constraining the role of geological structure and processes on the dynamics of active ocean-continent plate boundaries and elucidating the growth and fate of large Cordilleras, as revealed by geophysical data. I address these objectives by developing seismic velocity models of continental and oceanic plate systems and their seismic activity using data obtained from large networks of broadband seismic instruments, both on land and offshore. In particular, I use and develop seismic analysis tools rooted in modern statistical theory to extract maximum information from these data. My research focuses on the tectonics of western Canada, which form large natural laboratories to study these scientific objectives. On the western Canadian coastline, the Pacific and Juan de Fuca oceanic plates are juxtaposed against the North American continent along two plate boundaries: the Cascadia subduction zone to the south and the Queen Charlotte-Fairweather Fault to the north. Each boundary type contains large faults that are frictionally locked for long periods of time, and slip in large (and sometimes giant) earthquakes, and therefore represent significant seismic hazard to coastal populations. The majority of these earthquakes and the faults themselves are located offshore; their study therefore requires onshore-offshore seismic data. In addition to the threat they pose to coastal areas, subduction zones leave their imprint on the continental margin by forming volcanic arcs and large back arcs that evolve into cordilleras mountain belts that are hot and easy to deform over long time scales (~Myr). The Canadian Cordillera has been active since the Mezosoic and contains important mineral and geothermal energy resources. Its current seismic activity also reflects heterogeneous stress distribution that is partly controlled by its structural and geological makeup. In this proposal I plan to use all available sources of broadband seismic data encompassing western Canada to study these large tectonic systems; importantly, my long-term vision is to work toward new broadband ocean-bottom seismograph deployments in the northeast Pacific and western Canadian Arctic and capitalize on the presence of the large USArray Transportable Array deployment and on the opportunities created by the prospective Canadian Cordillera Array initiative to study these systems and address the scientific objectives.