Monitoring of the Ground Subsidence in Macao Using the PSI Technique

Abstract

In this paper, we investigated the long-term reclamation-induced ground subsidence in Macao, a coastal city of southern China. Persistent Scatterers Interferometry (PSI) technique was applied to retrieve the deformation rate in Macao during the period from April 2003 to August 2010 with a total of 41 scenes of descending ASAR data sets. The PSI-retrieved results showed a relatively stable pattern in Macao Peninsula, Taipa Island and Coloane Island, with an average subsidence velocity of -3 mm/y. In contrast, relatively large subsidence rates were highlighted in Cotai area, a newly reclamation land in 1990s, in which an average subsidence velocity was about -10 mm/y. A consistent relationship between the PSI results and the leveling measurements indicated that this PSI technique is an effective tool to monitor the reclamation-induced ground subsidence with a high accuracy and adequate spatial details. Accordingly the valuable ground subsidence results generated by PSI can be used not only for early detection and remedial activities of potential settlement of buildings, but also for helping the local government to formulate regional sustainable development planning and decision-making in disaster prevention and mitigation.