## 3 Results
### Seismic Scenarios  
#### 3.2.1 Validation of the Aigion 1995 Mainshock Simulation  
In order to assess the ground motion variability caused by the Aigion 1995 mainshock, PGA values were computed on a grid enclosing the area under study, with nodes at a spacing of 0.03\({}^{\circ}\) in latitude and longitude. The spatial distribution of synthetic PGA values is depicted in Figure 6a, along with the surface projection of the activated fault [29] and the available recorded PGA. The highest values estimated onshore exceeded 500 cm/s\({}^{2}\), whereas in the city of Aigion, where the highest observed PGA was reported, they were close to 300 cm/s\({}^{2}\). The spatial distribution of simulated values was similar to those presented in other studies [88,111], despite using diverse input parameters. The validation of the final parameters used in the simulation is shown in Figure 6b, where simulated PGA values are plotted against those derived from the selected GMPEs and the recorded ones as a function of Joymer and Boore distances (R\({}_{\text{jp}}\)). The functional form of the GMPEs used corresponded to a normal faulting style and type C (NEHRP) soil condition. As shown in Figure 6b, the PGAs obtained from EXSIM were in good agreement with the GMPE curves throughout the entire R\({}_{\text{jp}}\) range, except for the points that lay very close to the surface projection of the fault plane (R\({}_{\text{jp}}\)\(\leq\) 2-3 km). This was, however, anticipated, given that GMPEs are generally not fully capable of reliably reproducing the ground motion in very short distances due to the limited availability of near-fault strong motion datasets, which affects their formulation. Moreover, directivity effects may have a strong influence on near-fault ground motion that is not fully captured by the GMPEs used. In this case, for example, the high PGA value recorded in Aigion (AIGA; Figure 6b) has been attributed to forward rupture directivity, in addition to local soil and topographic characteristics [29,111]. Nevertheless, the overall PGA variability lay inside the \(\pm 1\sigma\) range for both GMPEs in the entire R\({}_{\text{jp}}\) range. Regarding the attenuation pattern, PGAs prescribed by the A14 and B14 models appeared to decay slightly faster than the simulated ones; however, taking into account the fact that the same finding also applied to the recorded ones (red triangles;  
Figure 5: Hazard curves in terms of **(a)** PGA for Aigion, Nafpaktos, and Patras and **(b)** UHS for the aforementioned sites, alongside the Ec8 and EAK2003 response spectra. The red rectangle indicates the range of eigenperiods of most buildings in the study area.  
Figure 6b), this highlights the importance of retrieving region-specific parameters that can be incorporated into GMPEs. The finally adopted synthetic PGA values were obtained based on the desire to achieve the right balance between keeping the lowest misfit among synthetic, GMPE-derived, and real values. Consequently, as shown in Figure 6b, our simulations were capable of reproducing the PGAs recorded from the two closest stations (AIGA, AMIA) more closely than the GMPEs, whereas at larger distances the general trend of the recorded PGAs (which presented a relatively high variability in certain cases) was captured by both GMPEs and synthetic values.