## 4 Results  
### Localization Solutions  
This section presents the results of the two mainshocks, the most significant, and further light to moderate aftershocks of the sequence separately. To accurately calculate the epicenter for the mainshock and the second strong event, we used local and regional broadband data from the HUSN. Thirty-three seismological broadband stations recorded the mainshock at epicentral distances shorter than 265 km. Some of these stations record continuously; others use a trigger system. These stations are three-component broadband stations from the Hellenic Unified Seismological Network (HUSN) available in this area, mostly CMG-3 ESP/100 se of 100s and a smaller number from these with Trillium120P. We used these data to analyze the events reported by the HUSN for the two mainshocks on 3 and 4 March 2021. We considered a 1D velocity model, previously built by inverting more than 124 P and S arrivals from the HUSN database, using the inversion approach [48] and the earthquake location methods [57; 58; 59; 60; 61]. Probabilistic locations were obtained using the NonLinLoc code [62]. On 3 and 4 March 2021 (10:16:08.3 UTC and 18:38:19.1 UTC), two strong earthquakes of similar Magnitude, M\({}_{\text{L}}\) 6.0 and M\({}_{\text{L}}\) 5.9, occurred in Thessaly, Central Greece. These events induced extensive structural damage, and a rich aftershock sequence followed these events (Figure 4). Three thousand seven hundred eighty-seven events were recorded from the beginning of the sequence until 31 December 2021, while only in the first month, 2268. For these three events, the source parameters were calculated and compared to the observed solutions from other institutes, and for the majority of them, a good agreement was found (Table 2). \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline  & & & & & & & & & & & \\ \hline \multirow{2}{*}{**Institute**} & **Latitude** & **Longitude** & **M\({}_{\text{w}}\)** & **M\({}_{\text{0}}\)** & **Depth** & **Strike** & **Dip** & **Rake** & **Strike** & **Dip** & **Rake** \\  & **(\({}^{\circ}\))** & **(\({}^{\circ}\))** & **(dyn\({}^{\circ}\)cm)** & **(km)** & **(\({}^{\circ}\))** & **(\({}^{\circ}\))** & **(\({}^{\circ}\))** & **(\({}^{\circ}\))** & **(\({}^{\circ}\))** & **(\({}^{\circ}\))** & **(\({}^{\circ}\))** \\ \hline Our Study & 39.7453 & 22.2340 & 6.3 & \(3.173\times 10^{25}\) & \(11.0\) & \(147\) & \(57\) & \(-86\) & \(317\) & \(39\) & \(-113\) \\ USGS & 39.5594 & 21.9200 & 6.3 & \(3.330\times 10^{25}\) & \(11.5\) & \(139\) & \(55\) & \(-83\) & \(307\) & \(36\) & \(-100\) \\ NOAA & 39.7545 & 22.1992 & 6.3 & \(3.173\times 10^{25}\) & \(10.0\) & \(146\) & \(59\) & \(-79\) & \(305\) & \(33\) & \(-108\) \\ ERED & 39.8055 & 22.2578 & 6.2 & \(2.6149\times 10^{25}\) & \(7.1\) & \(147\) & \(48\) & \(-94\) & \(332\) & \(43\) & \(-85\) \\ GCMT & 39.6500 & 22.1400 & 6.3 & \(3.140\times 10^{25}\) & \(12.0\) & \(119\) & \(45\) & \(-109\) & \(324\) & \(48\) & \(-72\) \\ INGV & 39.7400 & 22.1900 & 6.2 & \(3.600\times 10^{25}\) & \(10.0\) & \(116\) & \(41\) & \(-114\) & \(327\) & \(53\) & \(-70\) \\ KOERI & 39.7100 & 22.1600 & 6.3 & \(2.990\times 10^{25}\) & \(10.0\) & \(126\) & \(37\) & \(-103\) & \(323\) & \(53\) & \(-79\) \\ GZZ & 39.7700 & 22.1400 & 6.3 & \(3.000\times 10^{25}\) & \(10.0\) & \(130\) & \(45\) & \(-90\) & \(310\) & \(44\) & \(-89\) \\ OCA & 39.7500 & 22.2100 & 6.2 & \(3.600\times 10^{25}\) & \(7.0\) & \(135\) & \(45\) & \(-90\) & \(315\) & \(45\) & \(-90\) \\ IPGP & 39.7640 & 22.1760 & 6.2 & \(3.600\times 10^{25}\) & \(10.0\) & \(321\) & \(33\) & \(-78\) & \(127\) & \(57\) & \(-98\) \\ CPPT & 39.7760 & 22.1800 & 6.3 & \(3.400\times 10^{25}\) & \(12.0\) & \(125\) & \(55\) & \(-100\) & \(321\) & \(36\) & \(-77\) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: List of moment tensor solutions published by various institutions and universities for 3 March 2021 (10:16:08.3, UTC) and 4 March 2021 (18:38:19.1, UTC).