Geophysics

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Earthquakes are the most dangerous geological hazards globally. To become more resilient to them, it is vital to identify the causative faults and determine the frequencies and magnitudes at which they fail. My proposed research program seeks a better understanding of active faulting and earthquake behaviour within and surrounding British Columbia using new and innovative measurements from the fields of earthquake geodesy (how the Earth deforms during and between earthquakes) and tectonic geomorphology (how Earth's surface topography evolves over many earthquake cycles).There are three interrelated program elements:(i) Using the first ever sea-floor geodetic measurements from offshore Vancouver Island, we will investigate the degree of interseismic locking on the the northern Cascadia megathrust, widely recognized as one of the outstanding questions in Cascadia tectonics. We hypothesize that the shallow part of the megathrust creeps slowly and silently, which would indicate a low likelihood for rupture to the trench in the next great earthquake. If confirmed, there would be less need for planning for an earthquake and tsunami of the size observed in eastern Japan in 2011.(ii) By taking advantage of a wealth of new remotely-sensed light detection and ranging (lidar) data on land, we will identify and characterize crustal faulting within the North America plate: from Vancouver Island in the west to the Rocky Mountains in the east and from Yukon in the north to the U.S. border in the south. These faults generate smaller earthquakes than the offshore megathrust, but are located much closer to population centres and critical infrastructure and could (locally) be even more damaging. Our systematic study of airborne lidar data at the scale of the province and our deployment of a state-of-the-art lidar drone for fine-scale fault mapping are both firsts.(iii) Accurate earthquake forecasts rely upon understanding the mechanics of earthquakes and faulting, including the factors that govern rupture nucleation, propagation, arrest, and recurrence. Working on continental earthquake ruptures globally and drawing upon emerging geodetic and seismological imaging techniques, we will test a suite of hypotheses that relate critical aspects of earthquake behaviour - many of which directly influence the distribution and intensity of ground shaking - to simple metrics for the long-term history of slip (or "structural maturity") of the host fault.