Land Subsidence Assessment of Bandung City, Indonesia in Geological Perspective, Based on Interferometric SAR Using C-band Data

Land subsidence is a problem in several big cities and areas in Indonesia; some of them occurred in Jakarta, Bandung, Semarang, and the North Coast of Java location. The subsidence conditions are different and highly dependent on many factors, including geological and excessive groundwater extraction. One of the cities experiencing severe subsidence conditions in Indonesia is Bandung. This research is based on Interferometric SAR analysis using C-Band Sentinel 1A frequency data released by the European Space Agency (ESA), recorded on 11 November 2018 and 18 November 2019. Based on the analysis of SAR interferometry, Bandung City experienced subsidence with an average size of 6 cm per year. The city of Bandung is located between the mountains and can be described as a bowl. The city of Bandung itself is formed from alluvial plains resulting from the sedimentation process from the surrounding mountains. Geologically, the city of Bandung can be described as a city composed of materials that have not undergone a perfect consolidation process. This condition causes the city of Bandung to be prone to land subsidence disasters. In addition, another factor that plays a dominant role in the process of excessive groundwater extraction by residential and primarily industrial activities scattered in the Bandung area. If not handled properly, the phenomenon of land subsidence in the city of Bandung will cause a very detrimental impact, reduce the carrying capacity of the environment, and threaten the sustainability of the city. Among the actual effects on the broader area in Bandung that is affected by floods, especially during the rainy season.