Phase unwrapping is one of the most important parts of InSAR techniques. In order to estimate the grand surface displacements, interferomtric phases modulated between 0 to 2π must be unwrapped. Based on the use of either the conventional method or persistent scatterer (PS), phases will be spread both regularly and irregularly. The phases of PSs can be unwrapped by reducing phases into a regular and continues grid with neatest neighbor interpolation method. In this paper, beside Minimum Cost Flow (MCF) as a global unwrapping method, three local unwrapping methods (Branch-cut, Phase Derivative Variance and Branch cut-Phase Derivative Variance) are introduced as well. These conventional unwrapping approached are implemented on an irregular interferogram processed from Sentinal1A satellite images acquired over the Sirjan basin. At the end, the results of these approaches are assesed with unwraped phase which is resulted in a conventional interferogram unwrapped with MCF method.

Introduction: Earthquake is a natural disaster which sometimes causes injury and loss of life to many people and generates tsunamis. As one of the most frequently occurring natural phenomena, it is considered by many as the most frightening and dangerous natural hazard. With recent developments of remote sensing, radar interferometry is accepted as an efficient and relatively accurate method of measuring ground surface displacement. The present study has investigated June 25, 2020 earthquake in Qotur (the city of Khoy). Materials & Methods: The present study have utilized InSAR and PSI techniques to estimate the amount of displacement caused by the earthquake. Remotely sensed images collected in the upstream passages were processed in Sarproz software. Radar interferometry and other advanced methods such as PSI have made detection of vertical surface displacements possible even in a few millimeter range. The present pairs of images have been selected with a good correlation from Sentinel-1 data. Results & Discussion: The present study seeks to estimate the extent of ground heave and subsidence caused by earthquakes. Images selected from statistical periods before and after the earthquake were processed, and outputs were presented as figures and diagrams. Graphs showed the accuracy of the work and annual cumulative displacement. Results indicated the presence of a surface displacement between-16 and +16. The most intense subsidence and ground heave have happened in the northeastern regions (Gogerd village) and the southern regions (Kotanabad, Mir Omar, Grenavik villages), respectively. Conclusion: Maximum displacements (heave and subsidence) and other data collected from the earthquake show that the Bashkala left-Lateral Strike-Slip fault has caused this earthquake.