Influence of Viscous Lubricant on Nucleation and Propagation of Frictional Ruptures

Fluids are pervasive in the Earth’s crust and saturate fractures faults. The combination of fluids gouge layers developing along faults can generate different viscosities. Such viscous were found to influence reactivation, frictional stability faults, eventually dynamics propagating earthquake ruptures. We reproduced laboratory earthquakes on analog material (PMMA) study lubricant fault stability, rupture nucleation, propagation under mixed lubrication conditions. Experiments conducted dry conditions, with presenting a viscosity ranging from 1 1000 mPa.s. Through photoelasticity, high-frequency strain gauge sensors, accelerometer measurements, we obtained new insights about characteristic nucleation length, velocity, local slip rate evolution during Our experiments show that presence generating lubricated conditions induces, (i) reduction resistance, (ii) an increase (iii) decrease fracture energy. In addition, larger fluids, strength length. Moreover, ruptures occurring showed pulse-like rather than crack-like behavior, suggesting induce transition natural demonstrate, supported by existing theory, this is mainly governed stress acting at onset which drastically reduced lubricant.