## 5 Results  
The interferogrammetric phase represents the difference in a recorded signal's distance acquired by two SAR's. It is expressed by wavelength, and it can be mapped on interferogram. Each visible fringe on the interferogram corresponds to the wavelength unit depending on a band used by the radar. In case of C-SAR images used in this study, the wavelength for C-band is 5.6 cm. Figure 5 shows four interferograms: On the upper left, there is the interferogram for the Sentinel-1A ascending orbit, and on the upper right, there is for Sentinel-1B descending orbit acquired in the period of one week before and one after the earthquake, while on the lower left and right insets the interferograms in the period of weeks after the earthquake have been shown determined from the Sentinel-1A ascending orbit and the Sentinel-1B descending orbit, respectively. Both (a) and (b) interferograms shown in Figure 5 show a good correlation with the signal dominated by deformations, not by atmosphere, orbit, or digital elevation model errors. In that way, the interferogram clearly indicates the existence of the deformation. The slight mutual differences are visible, but it is expected due to different incident angles ranging from 36.24 to 45.78 and 35.03 to 41.73 degrees for Sentinel-1A and Sentinel-1B, respectively. From the after-earthquake state-of-the-art interferograms, shown in (c) and (d) insets of Figure 5, the deformation is still visible but on the smaller scale, implicating that the ground displacements are still occurring as the ground continuously trembles a month after the earthquake. By unwrapping the interferometric phase, we obtained the displacement in line of sight (LOS) of the SAR radar. Although it is expected for the inverse orbits when analyzed separately to yield different results with mutually inverse sign, it is still interesting to see (Figure 6) the significant differences obtained: Amplitude of LOS displacements obtained by the Sentinel-1A has the range of 74 cm unlike the one obtained by the Sentinel-1B with the range of 53 cm. LOS displacement is not a value that expresses the exact ground movement of the Earth's surface, but it reveals the existence of land motion. By combining the inverse orbits and having in mind that the SAR is more sensitive to vertical motion than to horizontal, vertical movement can be roughly isolated and determined. On 9 January 2021, while we were working on this research, the Croatian Geological Institute (CGI) released their new findings [74] about the earthquake, mapping the direction of two faults that are intersecting near the epicenter of this earthquake. The NW-SE fault defined by Croatian Geological Institute is in accordance with the ESDF global Fault Model V6.1, but somewhat eastwards. It is obvious that both sources (ESDF V6.1 and CGI's faults) have the same fault mapped, but we assume that the global model is a rough estimate, and CGI is a more precise one due to thorough regional measurements made by CGI. Hence,we included the newly mapped faults of Pokupsko fault (stretching NW-SE) and Petrinja fault (stretching SW-NE) determined by [PERSON] from CGI [54; 74]. The two faults are dividing the area distressed by the earthquake in four quadrants. The faults can be clearly recognized from the LOS displacements in the period of the week before and after the mainshock, registered by the SAR satellite, seen in Figure 6.  
Based on Equation (1), we made an estimation of the Earth's surface ground displacement, in vertical up-down and horizontal east-west direction. The computation was made using LOS displacement incident angle values [14] at every pixel prior to conducting the terrain correction. During the DinSAR processing, pixel size was set to 27 m. Incident angle was obtained from the corresponding SAR images, ranging from 36.24 to 45.78 and 35.03 to 41.73 degrees for Sentinel-1A and Sentinel-1B, respectively.