Geodetic observations confirming land subsidence of Bandung Basin, Indonesia, and subsequent building damage

Land subsidence in the Bandung Basin has been historically detected and possibly caused by several factors, including groundwater withdrawal. It is presumed that land subsidence is still occurring, causing a wide-ranging impact on infrastructure and buildings. This study aimed to determine the current status of land subsidence in Bandung Basin by using the Interferometric Synthetic Aperture Radar (InSAR) and Global Positioning System (GPS). The source of Synthetic Aperture Radar (SAR) imagery used in this study is Sentinel-1 imagery from 2014 to 2021. Land subsidence was then estimated using the InSAR method and validated with the GPS results. Based on the interpretation of the InSAR results, the most significant land subsidence in the Bandung Basin occurred in the Gedebage and Dayeuhkolot districts. It is estimated that the average annual land subsidence for these districts is about 10 cm/yr, with a maximum amplitude of around 17 cm/yr. Considerable damages due to land subsidence were also found. InSAR-derived land subsidence showed a good agreement with the GPS-derived land subsidence. In conclusion, land subsidence has been confirmed by two independent methodologies in this region and tends to worsen in the Bandung Basin.