Evidence of Nonextensive Statistical Physics behavior of the Hellenic Subduction Zone seismicity

- The seismicity of the HSZ is investigated using the NESP.
- Interpretation of the estimated q-triplet along the HSZ.
- High qM values indicate seismic zones away from equilibrium.
- The proportional to volumetric energy A increases when qM decreases.
- The models used fit very well to the observed distributions.

The Hellenic Subduction Zone (HSZ) is the most seismically active region in Europe. Many destructive earthquakes have taken place along the HSZ in the past. In this study we investigate the seismicity of the HSZ based on the science of complex systems. The spatiotemporal distributions of seismicity as well as the magnitude distribution are studied using the concept of Nonextensive Statistical Physics (NESP). Defining five seismic zones and forming an earthquake dataset that covers the period 1976-2009, we apply the NESP ideas to formulate the cumulative distribution functions of the inter-event times and distances and the magnitude distribution along the HSZ. Our results indicate that the nonextensive parameter qT, which is related with the inter-event time distribution, presents almost similar values in each of the seismic zones and reflects the long term scale of the seismicity evolution in the HSZ. The qD parameter, which is related with the inter-event distance distribution, presents a significant variation along the seismic zones. This variation is related with the different degree of spatial earthquake clustering in each of the seismic zones of the HSZ. Moreover, in the framework of the fragment-asperity model, the thermostatistical parameter qM, which is related with the frequency-magnitude distribution, could be used as an additional index to inform us about the physical state of each seismic zone along the HSZ. The variations of the qM parameter are related with the energy release rate in each seismic zone. The models used, fit rather well to the observed distributions, implying the usefulness of NESP in investigating such phenomena exhibiting scale-free nature and long range memory effects.