Time-series displacement of land subsidence in fuzhou downtown, monitored by SBAS-InSAR Technique

Abstract

The land subsidence in response to the construction of underground engineering, e.g., subway, has caused many geological hazards and impeded the sustainable development of urbanization, in particular of China. Analysis of land subsidence with high temporal-spatial resolution is necessary and can help to assess the risk of geohazards. In this study, we apply the SBAS-InSAR technique to monitor the land subsidence in Fuzhou downtown after the program of metro construction. 24 scenes of X-band TerraSAR data from July 2013 to August 2015 and 32 scenes of C-band Sentinel-1 data from July 2015 to February 2018 were used in this experiment. Our results show a maximum subsidence rate of -12mm/yr, and eight subsidence funnels have been found during the observed period. After analyzing the subsidence of these regions in a long time span, it can be concluded that there are three regions which have a relatively stable disastrous subsidence effect, and there is a possibility of further intensified subsidence.