## 3 Results  
### Local 1D Velocity Models and Location of the Seismic Catalogue  
Taking into account the final residuals, a 1D P-wave velocity model (\"P-S final model\"; Figures 6 and 7) was determined. The distribution of the spatio-temporal errors obtained using the newly developed local velocity models is shown in Table 1. The horizontal and vertical shift of the hypocentres, which arose between the initial and final regional velocity model, is shown in the supplementary material. The majority of events in the final seismic catalogue lie between 2 and 16 km in depth. The shallow seismicity is distributed along the faults that intersect the shallow part of the crust [13], while a significant portion of intermediate-depth seismic activity (H \(\geq\) 40 km) is located near Antikythera Island (West; sub-area 1 in Figure 5), north of Heraklion (central part; sub-area 4 in Figure 6d), and between Eastern Crete and the Kassos and Karpathos Islands (East; sub-area 6 in Figure 5). This observation shows a fair correlation between the rapid increase in velocity at depths greater than 32 km in these areas (Figure 6f) and recent tomographic studies in the regions along the Hellenic Arc. [44; 45; 46; 47; 48; 49; 50; 51]. Figure 6: Initial [39] and final velocity models of V\({}_{\rm P}\) and V\({}_{\rm S}\) determined by the mean travel-time residuals for the areas of (**a**) Chania-Antikythera, (**b**) Rethymno, (**c**) Matala, (**d**) Central Crete, (**e**) SE Crete-Pliny Trench, and (**f**) Zakros-Karpathos. The best 1D local velocity models are displayed. Their error statistics are shown in both histogram and map projection in Figures S1-S12. The histograms depict the temporal (RMS) and spatial (ERH and ERZ) error distributions of the available data between the study's starting [39] and final models. The newly developed velocity models provide us \begin{table}
\begin{tabular}{c c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Model**} & \multirow{2}{*}{
\begin{tabular}{c} **Regional** \\ **Model** \\ **[33]** \\ \end{tabular} } & \multirow{2}{*}{**Area 1**} & \multirow{2}{*}{**Area 1**} & \multirow{2}{*}{**Area 2**} & \multirow{2}{*}{**Area 2**} & \multirow{2}{*}{**Area 3**} & \multirow{2}{*}{**Area 3**} & \multirow{2}{*}{**Area 4**} & \multirow{2}{*}{**Area 5**} & \multirow{2}{*}{**Area 5**} & \multirow{2}{*}{**Area 6**} \\  & & & [39] & & & & & & & & & & \\ \hline RMS (\(\bullet\)) & 0.48 & 0.39 & 0.42 & 0.27 & 0.34 & 0.18 & 0.20 & 0.24 & 0.25 & 0.27 & 0.25 & 0.29 & 0.24 \\ ERH (km) & 1.44 & 1.95 & 2.27 & 1.68 & 2.47 & 1.90 & 2.37 & 1.74 & 2.10 & 1.61 & 2.36 & 1.71 & 2.21 \\ ERZ (km) & 4.74 & 6.90 & 7.25 & 4.58 & 7.25 & 4.99 & 9.08 & 5.62 & 6.36 & 6.59 & 15.08 & 6.02 & 5.45 \\ Mean Depth (km) & 33.70 & 17.22 & 13.69 & 15.82 & 11.88 & 11.34 & 11.01 & 8.07 & 13.69 & 10.70 & 9.12 & 15.69 & 15.49 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Statistics of temporal errors (RMS), location uncertainties and mean depth for Crete’s regional and group-specific initial [39] and final velocity models derived by this study. Figure 7: \(\rm V_{P}/V_{S}\) ratio obtained using the Chatelain method [42] in the areas of (**a**) Chania, (**b**) Rethymno, (**c**) Matala, (**d**) Central Crete, (**e**) SE Crete-Pliny Trench, and (**f**) Zakros-Karpathos. with a better concentration of seismic events, more realistic hypocentre depth ranges, and a proper understanding of local structure activation. In the westernmost region (Antikythera-Chania), the velocity model of the crust varies between 5.8 and 6.7 km/s for approximately 32 km, while the respective values for the neighbouring area of Rethymno are between 5.6 and 6.8 km/s for crustal thickness of less than 31 km (Figure 6b). The structure is relatively simplified since they are composed of four and three layers, respectively. Ref. [52] shows a more detailed image of the upper crust using data from seismic surveys conducted in the area. Their P-wave velocity model is composed of four (4) layers in the uppermost 2 km and reaches 5.2-5.3 km/s below 4 km of depth.