Fault-based Earthquake Rupture Forecasts for Western Gulf of Corinth, Greece

Abstract:

The western Gulf of Corinth has not experienced a strong earthquake since 1995 (the Ms=6.2 event of Aigion on 15 June 1995; Bernard et al., 1997), although the Gulf is extending fast (over 12 mm/yr of N-S extension from continuous GPS data spanning a period of 9+ years) and its seismic history since 1769 exhibits twelve (12) shallow events with M>6.0. We undertook an analysis of rupture forecasts along the active faults in this area of central Greece, using most updated datasets (active fault maps, fault geometry, fault slip rates, trenching data on past earthquakes, historical and instrumental seismicity, strain) and models for earthquake budget extrapolated from observed seismicity, magnitude-frequency distributions and calculated earthquake rates vs. magnitude for individual faults. We present a unified rupture forecast model that comprises a time-independent (Poisson-process) earthquake rate model, and a time-dependent earthquake-probability model, based on recent earthquake rates and stress-renewal statistics conditioned on the date of last event. The resulting rupture rate maps may be used to update building codes and promote mitigation efforts.