Land subsidence detection using JERS-1 SAR Interferometry

Abstract

Repeat-pass Interferometric SAR (InSAR) technique is use ful tool for the monitor of surface deformation. This technique is applied to detect the deformed area due to land subsidence in Jakarta, Indonesia. In those areas, it is well known that the excessive pumping of ground water has caused land subsidence. Leveling survey and GPS networking survey are carried out in Jakarta, Bandung and Semarang. However, InSAR processing has not been performed for study areas so far because no digital elevation model (DEM) can be applied. In this study we have applied DEM which were derived from interferogram using JERS-1/SAR L-band data with suitable baseline length acquired from 1992 to 1998. As the result of this study, annual amount of subsidence is estimated as approximately 10cm (1993-1995) and 6cm (1995-1998). This is supported by the results of 6-10cm (1991-1997) by level survey and 4-6cm (1997-1999) by GPS survey. Furthermore ground truth was carried out to verify the estimated rates and areas of subsidence. Therefore, L-band SAR data enable us to make interferogram to be applied to InSAR processing even though the observation period is three or five years. This result encourages us that PALSAR which is successor of JERS-1/SAR must be more powerful tool for detecting surface deformation such as land subsidence and volcanic activities on long time scales with L-band and GPS.