Subsidence Mapping in Jakarta - Psi Processing of L-band Alos Palsar Data

Jakarta is a heavily populated city, which has been experiencing ongoing ground subsidence for several decades, due to heavy use of groundwater, soil characteristics and tectonic motion. It is expected that this ground motion will increasingly impact upon flood risk management and ongoing development of the city, in particular critical infrastructure. Persistent Scatterer Interferometry (PSI) is an ideal technique for deriving accurate and detailed historical motion studies over urban areas. However, available Cband data stacks for Jakarta do not include sufficient images for PSI. This work instead applies PSI processing to a stack of L-band images from JAXA’s ALOS PALSAR instrument. The PSI results show a variety of subsidence features across the city at various spatial scales, with some areas experiencing average annual velocities of up to ~180 mm/yr. Comparisons with Envisat and ERS DifSAR interferograms show a promising agreement in both the spatial distribution and magnitude of deformation within the city. Results are also compared with existing GPS measurements from the city.