Radar interferometry for monitoring land subsidence due to underground water extraction

The underground water extraction induced subsidence has the characteristics of slow rate, less predictable location and coverage. Over a long time period, the cumulated subsidence can be up to a few metres. This paper demonstrates the feasibility and capability of using conventional two-pass differential interferometric synthetic aperture radar (DInSAR) for monitoring the underground water extraction induced subsidence. Two case studies are given in this paper. One is at the geothermal fields in New Zealand and another is the urban subsidence due to underground water over exploitation in China. The ERS-2 C-band and JERS-1 L-band SAR data were used respectively. The ERS-2 DInSAR results showed strong temporal and spatial decorrelation. A 70 days DInSAR subsidence map has been validated against the ground surveying data quantitatively. For the urban subsidence example in China, the L-band DInSAR results showed high agreement with the surveying data for a subsidence rate of over 80mm/year. BIOGRAPHY OF PRESENTER Dr Linlin Ge is currently a Senior Lecturer of remote sensing and GPS at the University of New South Wales (UNSW). He received his BEng (1st Hons) in Optical Engineering from the Wuhan Technical University of Surveying and Mapping (1985), MSc in Crustal Deformation from the Institute of Seismology (1988), and PhD in GPS and remote sensing from the UNSW (2001). His current research interests include microwave and optical remote sensing, structural deformation monitoring, kinematic interpretation of CGPS data (the so-called “GPS seismometers”), interpretation of CGPS data by incorporating synthetic aperture radar interferometry (InSAR), mitigation of atmospheric disturbance in InSAR, and analysis of single-frequency GPS observations with the aid of dual-frequency GPS data.