Collaborative Research: Controls on along-strike variations in locked and creeping megathrust behavior at the Hikurangi convergent margin

The physical processes dictating the spectrum of fault slip modes (spanning destructive earthquakes to slow slip events and aseismic creep) and the links between these behaviors and long-term morphotectonic evolution of subduction systems are not understood. There is a fundamental need to address this important problem with an integrated, system-level approach combining geodynamical modeling with high-quality geophysical and geological constraints on subduction margin characteristics. This project will conduct an interdisciplinary, multinational collaborative program involving the USA, New Zealand, Japan and the UK to evaluate system-level controls on processes that govern both slip behavior and long-term deformation at subduction zones. The focus is on the Hikurangi margin in New Zealand, where GPS data show a transition in slip behavior from predominantly stick-slip in the south to aseismic creep in the northern North Island, and where a wide range of subduction-related processes and characteristics vary along-strike. The aim is to rigorously investigate the feedbacks between plate interface slip behavior, solid and fluid mass fluxes, and manifestations of plate boundary mechanics in the long-term geological record that likely reflect common driving processes linking forearc uplift, sediment transfer and underplating, plate boundary strength, and seismogenesis. The Principal Investigators will address this important problem through an integrated approach combining large-scale seismic imaging, paleoseismology, and geomorphology, focused through the lens of state-of-the-art numerical modelling.