## 4 Discussion and Conclusions  
Geodetic observational data, such as InSAR measurements, are by now regularly used to infer information concerning sources of surface displacements and to understand the underlying processes. The significant co-seismic surface deformation signal of 18 April 2021, Bandar-e Genaveh earthquake, is clearly depicted by the InSAR images used in this study. The analysis of the mainshock co-seismic deformation demonstrated that the observed signal can be ascribed to a unique reverse fault with a 20\({}^{\circ}\) low dip to the northeast, across a broad (\(\sim\)9.5 \(\times\) 5 km) rupture plane, corresponding to the pre-existing seismogenic thrust Zagros Foredeep Fault (Figure 6). In the southwest of Iran, it accommodates the convergence of low-depth values of density contrast discontinuity of the Arabian and Eurasian plates in the subduction zone [10,11]. Figure 5: Observed, modeled and residual maps for displacements obtained from ascending and descending orbits for Mw 5.8 mainshock. The red star shows the location of mainshock. The estimations of the causative fault agree with the previously known local structures, which cut simple sediment folding of Bakhtiari, Lahbari and Aghajari formations (Figure 1) in low folded zone in Dezful Embayment [17; 22]. This fault can control the local fault-related folding and the frontal fold growth of large surface anticlines [21]. Despite the highly complex tectonic setting in the Zagros region [38] and the presence of large, active and hidden faults [39] with scattered seismicity [40], which sometimes do not follow the trend of the Zagros folds, we successfully demonstrated that the M\({}_{\rm W}\) 5.8 Genaveh mainshock occurred at a shallow dip angle subduction zone, located near the shortening Arabian-Eurasian Plate boundary on the Zagros Foredeep Fault. The used approach can help improve our understanding of the seismic potential of the Zagros region and refine the associated seismic hazards. It does not seem to be distinct from segments of the ZFF that generate steep range front topography elsewhere in the Zagros. According to [22], the deformation had propagated from MFF to Dezful Embayment in the late Miocene and based on our results it still continues. The orientation of the retrieved fault plane is in good agreement with those published by other international Institutes (Table 1), and is in good agreement with the compressional tectonic regime in the area. The crustal seismicity occurring in the investigated area since 1900 with pure thrust faulting [21; 41] is in agreement with our results. Its moment release rate does not greatly exceed those observed either instrumentally or historically and the formers show a seismic behavior similar to the one inferred for this zone [21]. The earthquakes along the ZFF mostly have \(\sim\)20-60\({}^{\circ}\) dipping fault planes that is significantly similar to ours. The results show that this moderate-size earthquake was located within the sedimentary cover in Zagros with a crustal thickness of \(\sim\)10 km, a basement of \(\sim\)25 km and a Moho depth of \(\sim\)45 km [17; 18; 42], and does not reach to a Brittle/ Ductile transition zone with predominant dip of \(\sim\)7\({}^{\circ}\)[17]. To get more detailed rupture slip distribution, the fault plane is subdivided into subfaults instead of just assuming single fault. As shown in Figure 4, the primary slip mechanism is dip-slip motion concentrated in a single main patch at a depth of 3.5-4.5 km, extending in the strike direction. There is no substantial slip shallower than 2.5 km, which confirms that this earthquake is associated with buried faults. Even though InSAR is a very powerful instrument, it may not always be appropriate for estimating the effects of low to moderate events, such as earthquakes characterized by magnitudes ranging from 4.5 to \(<\)6.