Abstract

Shear cracks along interfaces are relevant to a broad class of engineering and geophysics applications, ranging from the failure of composite materials and bonded joints to earthquakes and landslides. Characterizing the rheology of interfaces and faults is of paramount importance to improve our understanding of frictional ruptures, as friction controls key processes of rupture nucleation, propagation, and arrest and influences various rupture outcomes, for example how damaging earthquakes can be. In this presentation, I will discuss recent advances in the characterization of rupture behavior and friction evolution using our newly developed imaging technique, based on digital image correlation (DIC) coupled with ultrahigh speed photography. One of the highlights of this new approach is its ability to experimentally capture the full-field evolution of particle velocities and strains of spontaneously propagating dynamic ruptures at a level of detail that until recently was possible to achieve only with numerical simulations. Dynamic imaging of stresses enables us to decode the nature of friction by tracking its evolution and studying its dependence on slip, slip velocity and their history. The measured friction behavior allows us to challenge existing friction laws and formulate new ones. This approach gives a new perspective on the study of friction and provides important insights into earthquake and rupture physics.