Abstract:
Large earthquakes occur as dynamic ruptures propagating along pre-existing interfaces in the Earth’s crust containing rock gouge, the fine granular material produced by wear during sliding. How large and damaging an earthquake can be depends on the evolution of the frictional strength on the fault. Yet, friction evolution remains one of the main unknowns in earthquake physics. This presentation will discuss our recent advances in the study of friction and earthquake dynamics, using laboratory experiments. Our experimental configuration features spontaneously evolving dynamic ruptures along a rock gouge interface. Dynamic ruptures are imaged using our newly developed imaging technique, based on ultrahigh-speed digital image correlation (DIC), which allows us to capture the full-field evolution of particle velocities, strains, and stresses. We find intermittent rupture propagation in rock gouge interfaces, featuring rupture re-nucleation due to dynamic stressing. Dynamic imaging of stresses also enables decoding the nature of friction in rock gouge. As ruptures re-nucleate and arrest, the frictional strength undergoes dramatic variations with significant weakening followed by rapid healing. This new approach gives a new perspective in the study of friction and provides important insights into earthquake physics.
You will find the complete schedule for Njord Seminar Series spring '22 here.
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