Direct comparison of labquake and earthquake aftershocks sequences

We study an experimental model of a fault consisting in a stationary shear band in a compressed granular sample in the post-failure regime, when all the deformation occurs along stationary shear bands. Using an interferometric method of measurement of micro-deformations, we measure the strain fluctuations inside the shear band. The macroscopic mean deformation in the bands is the result of the accumulation of local, intermittent, shear events that follow the same statistics as earthquakes. In particular we observe aftershocks sequences, i.e. a local excess of plastic events following larger ones. In my talk, I will focus on recent experimental results regarding the dependence of the series statistics on the driving velocity. We have studied sequences of aftershocks for different compression velocities and we have shown that the aftershock sequences we observe are deformation-dependent and not time-dependent. Furthermore, we propose an analytical framework for treating labquake and earthquake catalogs on an equal footing. We show that when memory is considered to be in deformation and not in time, all data collapse onto a single master curve, showing that the timescale is entirely fixed by the inverse of the strain rate.