Application of persistent scatterer InSAR and GIS for urban subsidence monitoring

The purpose of this paper is to demonstrate the application of C-band ERS-1/2 and ENVISAT radar images to investigate the urban subsidence due to groundwater extraction. Cities in Australia without groundwater being over-extracted are compared to cities in Australia and China with groundwater being over-extracted. The persistent scatterer InSAR results are interpreted and compared to investigate the effect of groundwater extraction to urban subsidence. The GIS software is used to interpret the persistent scatterer InSAR results. The combined methods between persistent scatterer InSAR and GIS allow an integration of information from various sources and hence improve the efficiency for interpreting the data. A total of 15, 18 and 27 images of ERS-1/2 images acquired from August 1992-December 1996, April 1992-April 1997 and August 1992-July 2002 for Canberra, Sydney and Newcastle respectively are chosen to be investigated with persistent scatterer InSAR. Together with the above images, ten ERS-1/2 images from June 1992-December 1996 and nine ENVISAT images from December 2003-June 2006 acquired over Perth (Australia) and Northern China respectively are also chosen for similar investigation. The results show that the deformation rate from the cities with groundwater over-extracted, are significantly larger than the cities without groundwater over-extracted. The results have demonstrated the effect of groundwater extraction to urban subsidence.