Optimization of Loop Closure Phase on LiCSBAS for Ground Deformation Monitoring in Southern Sumatra

Indonesian territory has an active tectonic, one of which is Southern Sumatra. This is due to the presence of a subduction zone in the west and the Sumatra fault which is parallel to each other. Such geological condition can lead to disasters (e.g earthquakes and tsunamis) whenever it occurs. Accordingly, monitoring ground deformation is an important analysis to do in this area. LiCSBAS becomes an effective open-source tool for observing time-series of ground deformation using InSAR. One of the stages, the loop closure phase is a critical step in generating the number of interferograms and pixels that will be used. The objective of this study is to observe ground deformation in Southern Sumatra by taking the optimal value of the loop closure threshold. The data processing results that the threshold value used is 1.6 rad. Meanwhile, the deformation pattern is generally divided into two areas, the western and eastern parts of Southern Sumatra. The western part close to the Sumatra Fault Zone shows a subsidence at a rate ∼115 mm/year and the eastern indicates an uplift ∼68 mm/year.