Land subsidence rate analysis of Jakarta Metropolitan Region based on D-InSAR processing of Sentinel data C-Band frequency

Abstract

Land subsidence in Jakarta has been reported by many studies using various geodetic techniques. High exploitation of groundwater is the main factor of increasing land subsidence rate in Jakarta. The impact of land subsidence can be seen in several forms such as the damage on buildings and infrastuctures and the change of surface water pattern flow. This paper presents the update status and analysis of land subsidence of Jakarta Metropolitan Region (Jabodetabek) based on Differential Interferometric Synthetic Aperture Radar (D-InSAR) technique. D-InSAR technique based on interferogram that developed from a coherence technology of active radar imaging. Two images acquired with the same nominal geometry is required to develop interferometry SAR by using phase as a fraction of the wave, and change to distance. The displacement map is the final result of interferometry SAR and external Digital Elevation Model (DEM) required to remove topographic phase. Displacement map using pair of Sentinel data that acquired on March 18, 2017 and March 13, 2018 was successfully developed. The highest rate of land subsidence with 6 cm/year occurred in eastern part and western part of north area of Jakarta, some part in West Jakarta, Central Jakarta, and South Jakarta. The similar rate also occurred in Bekasi City, Bekasi Regency, Depok City, and Tangerang Regency. The moderate rate of land subsidence occurred in Tangerang City and South Tangerang City with 2-3 cm/year. Jakarta Metropolitan Region is a susceptible area of flooding. In this study, land subsidence has a similar pattern with the emergence of flood inundation. Therefore, the increasing of areas with flood inundation is affected by land subsidence. Monitoring of land subsidence rate in Jakarta Metropolitan Region by using D-InSAR Sentinel data is highly required due to high temporal resolution and accurate data especially for flood management and other urban development management, and free access of the data.