Monitoring reclaimed lands subsidence in Hong Kong with InSAR technique by persistent and distributed scatterers

Abstract

This paper introduced an advanced SBAS algorithm to investigate the subsidence time-series of reclaimed lands. A new method for fusing persistent and distributed scatterers in time-series images was presented in this algorithm. Moreover, nonlocal filter based on DS was employed for the interferometric phase which improved results quality with high spatial resolution. The reclaimed lands near Hong Kong Science Park and Hong Kong Disneyland (HKD) were selected for the investigation by high-resolution TerraSAR-X images. The reclaimed lands area was classified into three types labeled as undeveloped area, developing area and developed area. The results showed that: Undeveloped area had significant subsidence due to soft soil consolidation, especially in HKD’s reclaimed lands with deformation rate up to −459 mm/year; developing and developed area also had subsidence phenomenon due to building pressure caused by mass constructions of infrastructure. In particular, in the preliminary stage after construction, there was a dramatic subsidence trend, which easily threatened the security and stability of infrastructure facilities such as underground pipes and drainage system.