Analysis of active ground subsidence zones in Guangzhou city using ASAR Persistent Scatterer Interferometry

A Persistent Scatterer Interferometry (PSI) technology is used to detect ground deformation from ASAR images acquired from 2007-2008 in the urban area of Guangzhou in South China. To obtain active ground subsidence zones a great value filter method is developed to extract characteristic points with great values. Based on the ground deformation rate maps of the study area, a thematic map of the active ground subsidence zones is generated. To interpret the distribution of active ground subsidence zones, a local geological map of faults and rock type information is used to generate a series of thematic maps. The results show that geological faults, rock distribution, over-development, and underground engineering projects may be four factors leading to the distribution of the active ground subsidence zones in the study.