Time Series Land Subsidence Analysis Based on Persistent Scattered Interferometric Synthetic Aperture Radar Method of Jakarta City Region Using Terra SAR X Spaceborne Data

Scientists have widely used remote sensing technology to observe surface phenomena, either happened by naturally or artificially. Land subsidence monitoring is one of the promising discoveries made by implementing remote sensing technology, particularly with radar images. The gap in radar image processing technology has been attempted to solve in this study with a real case study in Jakarta, Indonesia. The challenge of simplifying the complex processing step that involved different correction due to time acquisition in radar images have been explained in this study. Aside from that, many researchers believe excessive groundwater extraction and over-exploitation of groundwater can be caused land subsidence, though other factors like land deformation and geological change can accelerate the possibilities. Prior studies have illustrated the subsidence level and methodology to investigate how subsurface change can be indicated by radar image scattering. According to that, this study focused on subsidence escalation in Jakarta. Although other areas can have similar issues, further study will be required. In this study, the Persistent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR) method has been used in Terra SAR-X multitemporal data; the process strives to search for the indication of land subsidence in the study area. The benefit of this PS-InSAR is its capability to extract point clouds at a particular temporal coherence setting from the SAR image, representing a current surface level. The data has been collected and processed from 29 scenes from 2017 to 2021, thus showing the changes over the last four years. Analysis during that period found that land subsidence existed at a high rate, compared with 2017 data, perceived that in 2021 subsidence level was cumulatively around 9.85 cm in the Pantai Indah Kapuk, North Jakarta area, and 5.63 cm in the Kembangan area of West Jakarta. A ground check is needed to ensure this strongly connects with geological factors. Still, PS-InSAR can be a beneficial tool for the surface modelling in a broad area and rapid mapping for geoscience analysis.