Analysis of natural time domain entropy fluctuations of synthetic seismicity generated by a simple stick–slip system with asperities

In the framework of the information theory, entropy measures the level of disorder of a system or its uncertainty. Varotsos et al. (2004) introduced the concept of entropy in natural time domain as a discriminating statistics. In this paper, we analyzed the fluctuations of entropy, δS, of synthetic seismicity produced by an experimental stick–slip system in order to investigate its Markovian behavior. Our system, whose asperities are given by sandpapers of different granularity degrees, mimics the dynamics of tectonic plates. We found that δS is able to characterize the synthetic seismic process as non-Markovian for higher threshold magnitudes and lower lengths of the time window sweeping through the dataset.