CAREER: Bridging Multiscale Observations and Models of Megathrust Faulting and Subduction Zone Hazards

About This Grant

Large earthquakes occurring at converging tectonic plate boundaries pose significant threats to communities worldwide. These so-called subduction zone earthquakes can trigger tsunamis and cause widespread damage, but scientists still cannot predict when they will occur. The most damaging events happen rarely, often centuries apart in a region, and their observations are scarce and rely on indirect inference. While physics-based models of subduction zones help explain these phenomena, they struggle to capture how small and large earthquakes interact over a wide range of timescales. To better understand megathrust systems and assess hazards, this project will develop new computational tools that combine real-world geophysical observations and models based on physics. The research team will study major earthquakes in Chile, Japan, and Alaska that occurred over the past 20 years to investigate their immediate and long-lasting impacts in these regions. Through partnerships with local organizations and teachers, the team will develop community-oriented learning materials for university courses as well as high schools and organize outreach events. The project will support and train undergraduate interns, graduate students, and a postdoctoral scholar, contributing to training and inspiring the next-generation geoscience workforce. This project will advance state-of-the-art methods for inferring and modeling megathrust faulting processes across timescales ranging from seconds to centuries after the initial earthquake ruptures in three major subduction zones. Using Bayesian inference techniques, the team will determine the kinematic properties of large earthquakes using seismic, geodetic, and tsunami data, enabling exploration of rupture properties and predictive analysis of crustal deformation and stress changes. These model ensembles will serve as inputs for multi-physics models incorporating laboratory-based rock friction and rheology to forecast the longer-term evolution of deformation and stress in three-dimensional Earth structures, accompanied by rigorous uncertainty quantification. The team will use these outputs to investigate how earthquakes of different sizes are connected, how fault zone processes relate to geological structure, and how interseismic fault coupling influences future seismic events. The research will illuminate fault stress and strength heterogeneity and controlling factors of subduction zone seismogenesis, with the resulting datasets and modeling tools benefiting future research in earthquake science and engineering and other disciplines. Project outcomes will include physics-based estimates for plausible hazard scenarios and probabilistic forecasts of deformation and aftershocks for selected high-risk subduction zones. Through collaboration with local communities in Chile, these estimates and projections of future hazards will inform policy decisions, ultimately contributing to mitigating economic and human losses from subduction zone hazards. This integrated project will advance both fundamental understanding and public awareness of these complex tectonic processes through coordinated research and educational efforts. 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.