## 4 Results
### Atmospheric Data Analysis  
We focused on the skin temperature (SKT) and outgoing longwave radiation (OLR) over four months before the first major seismic event, comparing the data with the historical time series of the past forty-two years, i.e., from 1980 to 2022.  
In the 120 days before the seismic event, no anomaly on SKT was found (Figure 9).  
Figure 10 evidenced the OLR data with the individuation of an anomaly with a two-day persistence on 21 January 2023 (i.e., 16 days before the mainshock). In order to assure the correlation of this anomaly with the imminent EQ, we visualised the corresponding spatial distribution allowing us to check the position of this maximum value. As shown in Figure 11, this maximum had a spatial position at the west of the epicentre.  
Figure 10: Analysis of the OLR parameter for Turkey EQ with comparison between the 2023 time series (dashed red line) and the historical time series (1980–2022, blue line). Evidenced by the red circle, there is one anomalous value with a persistence of 2 days referred to 21 January 2023 (i.e., 15 and 16 days before the mainshock). In each legend, std stands for standard deviation; 1-std, 1.5-std, 2-std mean one, one and half and two standard deviations, respectively.  
Figure 9: Analysis of the SKT parameter for Turkey EQ with comparison between the 2023 time series (dashed red line) and the historical time series (1980–2022, blue line). No anomalies were evidenced. In each legend, std stands for standard deviation; 1-std, 1.5-std, 2-std mean one, one and half and two standard deviations, respectively.  
Figures 12-14 show the CAPRI algorithm applied to MERRA-2 gas time series and the maps of the days characterised by the main anomaly, in the selected geographical area.  
Figure 11: Map of the OLR anomalous day (21 January) in terms of difference with respect to the historical mean. The epicentre is indicated by the central star. The darker red part of the region could be related to a pre-earthquake OLR anomaly.  
Figure 12: Sulphur dioxide (SO\({}_{2}\)) concentration in the four months before the mainshock (dashed red line) compared with the historical time series of the previous almost 19 years. The blue line is the historical mean, while the coloured bands present the 1 (light blue), 1.5 (green), and 2 (yellow) standard deviations. The red circle indicates an anomaly that emerges clearly from the 2\(\sigma\) background. Bottom: main anomaly maps form 2-day persistent signals.  
SO\({}_{2}\), CO\({}_{2}\), and CO show main anomalies occurred on 24-25 January and 3 February, i.e., 13, 12, and 3 days before the earthquake, respectively. The SO\({}_{2}\) anomaly has a two-day persistence, while CO\({}_{2}\) and CO had a 3-day and 7-day persistence, respectively.  
Looking at the anomaly maps, we can see that the concentration of maximum values is close to the EQ epicentre.  
Figure 14: Carbon monoxide (CO) concentration in the four months before the mainshock compared (dashed red line) with the historical time series of the previous almost 19 years. The blue line is the historical mean, while the coloured bands present the 1 (light blue), 1.5 (green), and 2 (yellow) standard deviations. The red circle indicates an anomaly that emerges clearly from the 2\(\sigma\) background. Bottom: main anomaly maps form 11-day and 9-day persistent signals, respectively.  
Figure 13: Carbon dioxide (CO\({}_{2}\)) concentration in the four months before the mainshock (dashed red line) compared with the historical time series of the previous almost 19 years. The blue line is the historical mean, while the coloured bands present the 1 (light blue), 1.5 (green), and 2 (yellow) standard deviations. The red circle indicates an anomaly that emerges clearly from the 2\(\sigma\) background. Bottom: main anomaly maps form 3-day and 3-day persistent signals, respectively.