## 4 Discussion
As mentioned above, its western part is largely affected by the active Gulf of Corinth, which has hosted high-magnitude events. On the contrary, the southeastern part of Attica is bounded by generally aseismic areas (in terms of crustal seismicity). Sub-area 2 (Salamina and Aegina) exhibited a slight deviation from the reference value of 240 cm/s\({}^{2}\), with PGA being mostly close to it. Again, the effect of the Gulf of Corinth was seen in the west-northwestern part of sub-area 2, where PGA was slightly higher. In sub-area 3, the estimated PGA failed to reach the levels of EAK2003, being ~50 cm/s\({}^{2}\) lower. The PGA reference value for sub-area 4 (Hydra and Spetses) was ~160 cm/s\({}^{2}\), similar to the ones predicted by the active building code. The northern part of the area slightly surpassed 160 cm/s\({}^{2}\). The maximum PGA value in sub-area 5 (Kythira and Antikythira) did not exceed the value provided by EAK2003 (240 cm/s\({}^{2}\)). In the work of [PERSON] et al. [97], computations of PGA and PGV values were performed for the entire Greek region. Although they provided similar ground motion distribution values to those found in the present study, it should be noted that in their work the slab tectonic environment was not taken into account. Consequently, their computational scheme generated higher PGA and PGV values than the methodology presented in this study. Another study, by [PERSON] et al. [53], also evaluated the seismic hazard of Greece by assessing PGA and PGV values at 45 sites within the country, with Athens being among them. Their study estimated a PGA and PGV of 140 cm/s\({}^{2}\) and 5-15 cm/s, respectively, for a return period of 475 years for the capital of Greece, which is consistent with the values computed in the present study. PGA hazard curves were generated for various locations, including Athens center, Methana, and the capitals of Salamina, Aegina, Poros, Hydra, Spetses, Kythira, and Antikythira Islands by taking local soil conditions into consideration. The incorporation of soil conditions was deemed necessary due to the considerable increase in PGA values compared to those calculated based on rock conditions (Table 2). The findings of this study indicate that all sites, except for the capital of Hydra, exhibited PGA values that are consistent with the reference value of EAK2003. Notably, the capital of Antikythira possessed the highest level of seismic hazard, whereas the city center of Athens presented the lowest. It is important to note that strong ground motions in the order of 1000 cm/s\({}^{2}\) did not occur for any probability, indicating that such extreme values are not likely for probabilities of exceedance in the range of [0.010, 0.999] for a 50-year time span. The ultimate product of PSHA was the determination of spectral acceleration values for the period range of [0.1, 2.0] s in order to construct the Uniform Hazard Spectra for the same sites mentioned in the PGA hazard curve section. During this stage, the computational approach was modified to incorporate the estimation of S\({}_{\text{a}}\) based on the GMPE developed by [PERSON] and [PERSON] [78] for crustal earthquakes only, thereby excluding the major slab branch, as there is no available GMPE for the latter. Nevertheless, the adopted model was parameterized to account for all types of focal mechanisms for each area source. As also observed in the PGA hazard curve analysis, the capital of Antikythira Island had the highest spectral acceleration value, whereas Athens city center had the lowest. This study presents an up-to-date seismic hazard assessment in the administrative region of Attica by incorporating both crustal and slab tectonic environments. Most previous work on seismic hazard for the Greek territory typically considered only crustal area sources. By also incorporating the slab, we managed to compute distinct threshold magnitude annual exceedance rates for the deep area sources, leading to a more accurate characterization of seismic hazard.