###### Abstract  
Probabilistic Seismic Hazard Assessment (PSHA) was carried out for the administrative region of Attica (Greece). Peak Ground Acceleration (PGA) and Peak Ground Velocity (PGV) values were calculated for return periods of 475 and 950 years for five sub-areas covering the entire region. PGA hazard curves and Uniform Hazard Spectra (UHS) in terms of spectral acceleration (S\({}_{\mathrm{A}}\)) values were generated for Athens, Methane, and the capitals of each island of Attica (Salamina, Aegina, Peros, Hydra, Spetses, Klythira, and Antikythira). Area sources were adopted from the Euro-Mediterranean Seismic Hazard Model 2013 (ESHM13) and its update, ESHM20, taking into account both crustal and slab tectonic environments. Ground Motion Prediction Equations (GMPEs) proposed for the Greek territory were ranked for PGA and PGV. Each GMPE was reconstructed as a weighted model, accounting for normal and non-normal focal mechanisms for each area source. PGA, PGV, and S\({}_{\mathrm{A}}\) values were computed using a logic tree, integrating the seismotectonic models as major branches and sub-logic trees, comprised of multiple ranked GMPEs for each area source, as minor branches. The results showed higher seismic hazard values in sub-areas near the Gulf of Corinth and the slab interface, which could indicate a need to revise the active building code in Attica. PSHA; PGA; PGV; UHS; spectral acceleration; logic tree; GMPE ranking Article  
A Logic-Tree Approach for Probabilistic Seismic Assessment in the Administrative Region of Attica (Greece)  
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Footnote 1: email: {[[https://doi.org/10.3390/](https://doi.org/10.3390/)]([https://doi.org/10.3390/](https://doi.org/10.3390/))  
**Citation**: [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON]; [PERSON] [PERSON] A Logic-Tree Approach for Probabilistic Seismic Hazard Assessment in the Administrative Region of Attica (Greece)  
(Greece). _Appl. Sci._**2023**, 13, 7553. [[https://doi.org/10.3390/](https://doi.org/10.3390/)]([https://doi.org/10.3390/](https://doi.org/10.3390/))  
**Academic Editor: [PERSON]  
Received: 28 March 2023  
Received: 19 June 2023  
Received: 25 June 2023  
Received: 28 March 2023  
Received: 19 June 2023  
Received: 25 June 2023  
Received: 28 June 2023  
Received: 19 June 2023  
was homogenously extended up to 2019 (Figure 1). Regional and local monitoring has been remarkably improved since the establishment of the Hellenic Unified Seismic Network (HUSN; [5]) in 2008. Some of the more notable historical earthquakes that affected Attica's mainland include the 480 BCE, M = 6.3 Salamina earthquake; the 420 BCE, M = 6.0 earthquake, which impacted Athens and Corinth; the 1321 CE, M = 6.5 earthquake near Thiva, with an estimated macroseismic intensity of I = VIII; the June 1402, M = 6.8 earthquake at Xylokastro, with I = IX; the August 1417, M = 6.4 earthquake at Euboea; and the 17 September 1805, M < 6.0 event close to Athens, with I = VII [2]. Destructive earthquakes of estimated magnitudes of 6.6 and 7.0 [2] occurred on 20 and 27 April 1894, respectively, at Atalanti [7,8]. The most consequential earthquake that affected the mainland of Attica during the instrumental era was the M\({}_{\rm w}\) = 6.0 event that occurred on 7 September 1999, at 11:56:50 UTC at the southern flank of Parnitha Mt, about 20 km NW of Athens, causing extensive damage, collapses, and human casualties. Despite not being one of the strongest earthquakes in Greece, its proximity to the country's capital and socioeconomic center had a detrimental  
Figure 1: Historical (white squares; after [PERSON] and [PERSON] [2]) and instrumental (1900–2019) seismicity (circles and stars, color-coded according to their focal depth; after [PERSON] et al. [4], extended up to 2019) in the broader area of the administrative region of Attica. The selected area is marked with a red rectangle in the inset map (NAT: North Aegean Trough; NAF: North Anatolian Fault).