## 4 Discussion
However, the adopted model was, again, parameterized to take into account all types of focal mechanisms for each zone. The values for the spectral acceleration were almost the same for all three cases, as was also observed in the hazard curves. Differences from the elastic design spectra of EAK2003 [109] and Ec8 [110] were evident. The fundamental periods of interest had ranges of [0.1, 0.5] s (Figure 5) for the majority of buildings in Greece. In this range of values, the spectra for Patras, Nafpaktos, and Aigion significantly surpassed EAK2003. However, they were fully overlaid by the design spectra from Ec8. Moreover, given that the probability of exceeding the respective S\({}_{\text{a}}\) value was equal for all periods, and since all future earthquake events were taken into account, it is reasonable that higher values were computed. Hence, it is suggested that the Ec8 regulations should be respected for the majority of buildings in the study area. In addition to the traditional PSHA approach, finite-fault stochastic simulations were performed by generating earthquake scenarios for a predicted maximum magnitude (M\({}_{\text{max}}\)), calculated by taking into account past seismicity and fault data. The three modeled active faults were the Psahopyrgos, Helike, and Trizonia Faults. Final results were obtained by testing both random earthquake nucleation points and co-seismic slip distribution on the surface. Prior to the computations, stochastic modeling parameters regarding the path and local site effects were calibrated by performing strong ground motion simulation of the largest recent event; namely, the Aigion earthquake that struck the study area in 1995. Comparison with real strong motion data and GMPEs proved that this methodology is reliable for the reproduction of the ground motion, regardless of the uncertainties that are involved, which can be ascribed mainly to source complexity and local site condition variability. As a result, this methodology can be treated as a powerful tool for the simulation of the expected strong ground motion of future strong earthquakes, especially for cases where recordings are sparse or not available. It, therefore, provides a unique opportunity to comprehensively evaluate seismic hazard with the synergy between PSHA outcomes and specific scenarios. Site-specific analysis at the three selected sites was performed through a comparison between response spectra for each seismic scenario. S\({}_{\text{a}}\) values constitute a good indicator of seismic loading for a variety of structures, as they describe the absolute maximum response of a single degree-of-freedom oscillator to an enforced ground motion. The mean response spectra exceeded the current EAK2003 in some cases, as in Nafpaktos for the hypothetical rupture of the Psahopyrgos Fault. The city of Patras was revealed to be the site less exposed to seismic hazard among those examined for the selected scenarios. However, it should be noted that other faults outside the WGoC may be more dangerous for Patras, such as the Rion-Patras fault zone (Figure 1); the local NW-SE sinistral-slip fault, which was related to the 1993 earthquake [41]; or even the Andravida fault, further southwest, which has caused strong earthquakes in the past [118]. The latter two faults were not taken into account, as the present study assessed seismic hazard in the WGoC area. Overall, the PGA variability obtained from the specific fault scenarios lay inside the PGA values calculated through the PSHA. Figure 3a,b indicate that the western part of the study area exhibited a similar level of seismic hazard under the PSHA evaluation. The expected peak ground motions in this part, however, were considerably affected by the nearby seismic sources to the west (the Ionian Islands and the westernmost end of the Hellenic Arc), which are among the most active and productive in terms of seismic potential [119].