We reveal transient surface deformation following the 2017 M_w7.3 Sarpol Zahab (Iran) earthquake using Interferometric Synthetic Aperture Radar (InSAR) measurements. Based on the coseismic interferograms derived from the Advanced Land Observing Satellite‐2 (ALOS‐2) data, the preferred slip model of the earthquake has a centroid depth of 14.5 ± 4 km and suggests that a basement fault is most likely responsible for the 2017 earthquake in the northwest Zagros fold‐thrust belt zone. Two slip asperities with a maximum slip of 6 m separated by 16 km are observed in the best fitting slip model. The accumulated afterslip in the first month after the mainshock determined from the Sentinel‐1 postseismic interferograms reveals a slip distribution that lies immediately updip of the coseismic slip, implying that frictional properties of the fault vary along the rupture patch. The Bamo Mount in the earthquake area was uplifted by approximately 1 m during the earthquake. We suggest that local topographic growth from both seismic and aseismic faulting behaviors is common within the Zagros fold‐thrust belt zone based on our findings regarding the 2017 earthquake and other significant events in the region.

In this paper, Landsat images are used in the mapping of transverse fault lineaments in Zagros, Iran, and the origin of the fault lineaments as the result of basement reactivation faults is examined using geomagnetic maps. The area under investigation is located in the SE part of the Zagros Fold Belt (ZFB) and was affected by influence of concealed faults, or fault lineaments, during the late Alpine Zagros orogeny. Image interpretation of geological structures such as curvilinear geometry of fold hinges, en echelon pattern of surficial lineaments and younger folds, and breached salt plugs, has been used to map the fault lineaments. Two sets of strike‐lateral transverse fault lineaments have been detected. The first set, NW‐trending, was identified by right lateral curved geometry of the main fold hinges, generation of younger folds, and en echelon pattern of surficial lineaments. The second set, NE‐trending, was verified based on left lateral displacement of the structures and alignment of salt plugs pierced anticline hinges. The placement of Upper Proterozoic salt plugs on the surface along the fault lineaments, together with their correlation with the magnetic‐driven lineaments, implies that the fault lineaments have a basement origin. The trend of these fault lineaments can be correlated with the trend of basement faults in the northern margin of the Arabian plate. The key result of this study is that the fault lineaments identified by integration of remotely sensed data and geomagnetic maps are generated as first order wrench faults by reactivation of the N–S‐trending basement faults. The thick Hormoz Salt formations overlaying the basement do not allow the fault lineaments to emerge at the surface. Therefore, they can be mapped through regional remote sensing and their basement origin can only be recognized by their correlation with magnetic faults. It is also concluded that satellite imagery can greatly contribute to the structural mapping of the ZFB and is therefore a valuable aid for oil and gas exploration in analogous tectonic environments.

Stratigraphy, detailed structural mapping and a crustal-scale cross section across the NW Zagros collision zone provide constraints on the spatial evolution of oblique convergence of the Arabian and Eurasian plates since the Late Cretaceous. The Zagros collision zone in NW Iran consists of the internal Sanandaj–Sirjan, Gaveh Rud and Ophiolite zones and the external Bisotoun, Radiolarite and High Zagros zones. The Main Zagros Thrust is the major structure of the Zagros suture zone. Two stages of oblique deformation are recognized in the external part of the NW Zagros in Iran. In the early stage, coexisting dextral strike-slip and reverse dominated domains in the Radiolarite zone developed in response to deformation partitioning due to oblique convergence. Dextral-reverse faults in the Bisotoun zone are also compatible with oblique convergence. In the late stage, deformation partitioning occurred during southeastward propagation of the Zagros orogeny towards its foreland resulting in synchronous development of orogen-parallel strike-slip and thrust faults. It is proposed that the first stage was related to Late Cretaceous oblique obduction, while the second stage resulted from Cenozoic collision. The Cenozoic orogen-parallel strike-slip component of Zagros oblique convergence is not confined to the Zagros suture zone (Main Recent Fault) but also occurred in the external part (Marekhil–Ravansar fault system). Thus, it is proposed that oblique convergence of Arabian and Eurasian plates in Zagros collision zone initiated with oblique obduction in the Late Cretaceous followed by oblique collision in the late Tertiary, consistent with global plate reconstructions.