Scaling properties of the Mw7.0 Samos (Greece), 2020 aftershock sequence

Abstract

On October 30, 2020, a strong and shallow earthquake (Mw = 7.0) hit Samos, an island on the eastern edge of the Aegean Sea (Greece). The epicenter was located on the north offshore of the Greek island of Samos. The goal of our work is to provide a first analysis of the scaling properties observed in the aftershock sequence as reported until December 31, 2020, as numerous seismic clusters activated. Our analysis is focused on the main of the clusters observed in the East area of the activated fault zone and strongly related with the mainshock’s fault. The aftershock sequence follows the Omori law with a value of p ≈ 1.01 for the main cluster which is remarkably close to a logarithmic evolution. The analysis of interevent times distribution, based on non-extensive statistical physics indicates a system in an anomalous equilibrium with a crossover from anomalous (q > 1) to normal (q = 1) statistical mechanics, as great interevent times approached. A discussion of the crossover observed, is given in terms of superstatistics. In addition, the obtained value q ≈ 1.67 suggests a system with one degree of freedom. Furthermore, a scaling of the migration of aftershock zone as a function of the logarithm of time is discussed in terms of rate strengthening rheology that govern the evolution of afterslip process.