Seismological studies of plate tectonic boundaries and rifted margins

The proposed research program is focused on plate boundaries and major transition zones in the Earth's solid outer layer, the lithosphere. The plate boundaries under investigation, namely subduction zones, mid-ocean ridges and transform faults, as well as the continent-ocean transitions found at rifted margins and internal to the plates, all form as part of the Earth's plate tectonic cycle. Subduction zones are places where oceanic and continental plates converge, where the thinner but denser oceanic plate sinks under the continental plate to eventually recycle into the Earth's mantle, and where the largest earthquakes on Earth occur. At transform margins, plates slide past one another, producing earthquakes with magnitudes second only to those occurring on subduction thrusts. Mid-ocean ridges are divergent plate tectonic boundaries where new oceanic crust is continuously generated. They make up the most extensive mountain system and the longest chain of volcanoes on Earth. Rifted continental margins form by extension and breakup of the continental lithosphere, a process that creates new ocean basins. The proposed research program will apply state-of-the-art data analysis methods to active and passive source seismic data. The goal is to investigate the targeted subsurface structures at unprecedented resolution in order to test leading scientific hypotheses and answer questions that have the potential to transform our understanding of plate boundaries. The selected study areas are: Cascadia Subduction Zone, Queen Charlotte Fault, Southwest Indian Ridge, and Western Baffin Bay. The study areas and problems to be addressed are chosen based on their suitability for achieving my short- and long-term science goals, the potential for high-impact discoveries, their economic and societal impacts, and interest to a broad group of earth scientists and general public. Earthquakes and the associated tsunamis, as well as volcanic eruptions pose significant hazards to Canadians and our infrastructure. Improved constraints on the geometry and character of seismogenic zones and seismicity in general, an anticipated outcome of the planned research, will lead to more accurate probabilistic seismic hazards maps and improved building codes. These are the primary means used to mitigate earthquake damage. New constraints on the deep structures at rifted margins, which host the largest recently drilled hydrocarbon deposits, will help guide future exploration. All of the projects that comprise the proposed research program are high-profile international collaborations because investigations of structures deep below the seabed, which is one of the Earth's last frontiers, require major resources, both human and technological. This cutting-edge collaborative environment presents an excellent opportunity to train HQP that will one day lead the next generation of researchers to new discoveries.