Modeling seismicity rate changes along the Hellenic subduction Zone (Greece).

Résumé

The Dieterich (1994) Rate/State formulation was applied for the seismicity rate changes in the western part of the Hellenic arc to be investigated. The completeness magnitude of the shallow seismicity (h<60km) was firstly evaluated for different time windows. The spatio-temporal changes of these seismicity rates (reference rates) were studied then for the interevent periods between successive strong
(M≥6.0) earthquakes. These changes were correlated with the Coulomb stress changes (ΔCFF) produced by the stronger events, through a Rate/State model which incorporates physical parameters associated with fault dynamics such as the tectonic stressing rate, fault constitutive parameters and frictional response of the rupture zones. The influence of the former parameters in the model performance was
tested by evaluating the linear correlation coefficient between modeled and real earthquake production rates along with their confidence limits. Application of different parameter values was attempted for the sensitivity of the calculated seismicity rates and their fit to the real data to be tested. Given the geographical peculiarity of the Hellenic Subduction zone, that yields to high uncertainties in the earthquake focal parameter determination, the results demonstrate that the present formulation and the available data sets are sufficient enough to contribute to a robust seismic hazard assessment.