Applications of InSAR and 2D Seismic Interpretation for Salt Tectonic Studies in the Salt Range and Potwar Plateau Region, Northern Pakistan

Salt tectonics in Northern Pakistan affects the geological structures and the seismology of the area. Salt layers are important in influencing the deformation style of geological structures. The difference in deformation intensity between the Potwar Plateau-Salt Range and the Kohat Plateau-Surghar Range systems is attributed to the presence of a Pre-Cambrian salt layer. Overburden will translate efficiently on the ductile salt detachment and will result in low internal deformation, which is evident in the Potwar Plateau-Salt Range system. In this system, the salt layers act as a lubricant between the overlying sedimentary layers and the basement rocks. In contrast, the Kohat Plateau-Surghar Range system has high internal deformation. This could be due to the absence or the thinning of the salt layers which causes increase friction between the overburden and the basement rocks. This study is an attempt to investigate the role of salt in the geological deformation of the Salt Range-Potwar Plateau using InSAR, 2-D seismic interpretations, and geomorphic index calculations. 3-pass interferometry was done using 8 ALOS PALSAR scenes, in order to create a surface displacement map with two years temporal difference. The InSAR and geomorphic index results suggest that the Salt Range may still be active tectonically and has undergone uplift. Six migrated seismic reflection lines were interpreted showing basement ramps due to normal faults. These ramps are believed to act as transition zones between different roles of salt; salt layer act as a decollement to the north and salt flow is prominent to the south. Furthermore, the results also suggest that differential loading is the main driving force for the salt flowing to the south. However, buoyancy force may play a significant role in the deformation of vi the Salt Range due to the uplift. Moreover, both the salt layer and the geometry of the basement influence the deformation style in this region. This thesis suggests that the Salt Range and Potwar Plateau region is a thin-skinned fold-and-thrust belt due to the wedge shape of the plateau and the salt as the weak detachment layer.