Abstract

Physical systems characterized by stick-slip dynamics often display avalanches. Regardless of the diversity of their microscopic structure, these systems are governed by power-law distributions for avalanche size and duration. I will focus on the interevent times between avalanches instead and, using results from experiments on granular systems and numerical simulations of emulsions, show that, unlike their distributions for size and duration, the interevent time distributions are able to distinguish different mechanical states of the system, characterized by different volume fractions or confining pressures. Remarkably, for large packing ratios, these interevent time distributions look similar to those for earthquakes and are indirect evidence of large non-trivial space-time correlations in the system.