Land subsidence under different land use in the eastern Beijing plain, China 2005-2013 revealed by InSAR timeseries analysis

Land subsidence has been occurring in Beijing since the 1970s. Five major land subsidence areas have been formed: Dongbalizhuang-Dajiaoting, Laiguangying, Changping Shahe-Ba Xianzhuang, Daxing Yufa-Lixian, and Shunyi-Ping Gezhuang. In this paper, we studied on land subsidence in Dongbalizhuang-Dajiaoting and Laiguangying using small baseline subset interferometry and interferometric point target methods of 47 ENVISAT ASAR and 29 RADARSAT-2 data. The results showed that the degree of land subsidence in these areas varied significantly. The mean land subsidence rate ranged from 143.43 to 8.2mm/a and from 132.11 to 7.3mm/a during 2005-2010 and 2011-2013, respectively. We correlated the observed settlement with the land use (agricultural, residential, and industrial). Displacement in the agricultural areas was greater than that in the other areas from 2005 to 2013. Moreover, we compared the observed deformation and the groundwater level in phreatic and confined aquifers. There was a strong correlation between ground subsidence and the groundwater level and the ground settlement increased with a decrease in the groundwater level and the maximum correlation coefficient can reach 0.525. Furthermore, subsidence appeared to be associated with compressible deposits, suggesting that for 90-210-m thick compressible deposits, ground settlement is more likely to occur as the thickness of the compressible layer increases.