Ground subsidence characteristics associated with urbanization in East China analyzed with a Sentinel-1A-based InSAR time series approach

Abstract

Fengxian County in East China has experienced rapid urban development over the past decades, resulting in environmental problems associated with rapid urbanization, such as pollution, resource depletion, land subsidence, among others. In this study, we analyzed ground subsidence in Fengxian and Peixian counties associated with urbanization and mining activities by interferometric synthetic aperture radar (InSAR) time series technology, using 26 Sentinel-1A SAR images taken between July 2015 and March 2017. The results reveal that during the study period serious subsidence occurred in Fengxian town and the area of northern Peixian county. The maximum subsidence rate of the study area reached 75 mm/a, with an average subsidence rate of 15.9 mm/a. The subsidence rate was higher in the newly established districts east of Fengxian town than in the old town district. The most severe ground displacement in Peixian County occurred in the Zhang-shuang-lou mining area, while Peixian town itself was stable. These different spatial distributions of ground subsidence in the two county towns are highly correlated with their differing types of economic activities. We conclude that the relationship between ground subsidence and urbanization in these two county towns provides the basis for scientific decision-making regarding urban development.