Measuring surface deformation of Beijing and surrounding area using X-band InSAR data

Abstract:

The InSAR technique has been widely used in surface deformation monitoring in recent years. Although the X-band InSAR data have relatively lower coherence in vegetation covering areas than the C-band and L-band data, they have the potential to capture finer deformation signals in cities with less influence from ionosphere disturbance. In this study, we utilize X-band TarraSAR data to investigate the accumulated surface deformation from 2008 to 2012 in Beijing and the surrounding regions including Cangzhou and part of Tianjin. Our preliminary result shows that in our research area, the nontectonic deformation signals, such as deformation caused by groundwater withdrawal and viaduct and subway constructions are considerably larger than that of tectonic deformation caused by active faults located in the Zhangjiakou-Bohai seismic zone. The main deformation signals discovered so far are from surface subsidence distributed in the east and north downtown area of Beijing, conforming our previous discoveries using the L-band SAR data. Our result also shows the phenomenon that spatial extents of some subsidence areas are aligned with local faults, this indicating that the groundwater flow may be manifested by physical barriers of faults. Our result will help assessing hazard potentials associated with land subsidence in Beijing and surrounding areas.