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• Investigate subsidence in Beijing with Sentinel-1 TOPS SAR data. • Demonstrates subsidence in Beijing (2015–2017) is still severe up to 14 cm/year. • Investigates detailed active geological faults information in Beijing. • Reveals subsidence is spatially controlled by geological faults to some degree. Beijing, the capital city of China, has been affected by land subsidence due to intensive groundwater extraction since 1935. Recent studies reported that the maximum subsidence occurred in the east of Beijing, reaching more than 11 cm/year till 2017. To investigate the subsidence (2015˜2017) in Beijing, in this paper, time series interferometric synthetic aperture radar (TS-InSAR) analysis was performed with 22 Sentinel-1 Terrain Observation by Progressive Scans (TOPS) mode SAR data. Results show that wide areas in the east of Beijing are subsiding with a maximum rate of 14 cm/year, which is consistent with GPS data. Detailed analysis of the obtained subsidence map reveals the existence of several characteristic near-linear boundaries within the subsiding areas. As a result of our previous three-year project, we generated the exact location, direction, and late Quaternary activity of the main potential active faults in the Beijing area. The relationship between the trace of these existing geological faults and the mentioned subsidence boundaries was investigated in detail. It is suggested that land subsidence in Beijing was mainly caused by the over-extraction of groundwater, with its spatial pattern being controlled by geological faults. [ABSTRACT FROM AUTHOR]

As one of the most water-scarce cities in the world, Beijing has been suffering from land subsidence for decades because of over-pumping of ground water. According to the latest released plan for the urban layout, the sub-center of Beijing, located in one of the subsiding zones of the eastern part of the capital, is designed to dredge the non-capital functions of Beijing and to accommodate 1.3 million permanent residents by 2035. It is well known that land subsidence can impact the safety of urban infrastructure, so it is important to monitor the evolution of land subsidence in the Beijing's sub-center along with its rapid urbanization processes. In this presentation, the ascending TerraSAR-X stripmap images collected during the period from 2010 to 2016 and the descending RADARSAT-2 data from 2010 to 2016 were utilized to obtain the annual subsidence rate and the corresponding displacement time-series in the sub-center of Beijing using the time series InSAR technique. Comparisons of our InSAR retrievals with the leveling measurements show a high correlation, indicating the reliability of our InSAR results. Our preliminary results show an accelerating rate of land subsidence during the period from 2010 to 2016. The spatio-temporal evolution characteristics of land subsidence in Beijing's sub-center were analyzed, and the conditioning and triggering factors of the subsidence was investigated using geological and hydrogeological datasets. [ABSTRACT FROM AUTHOR]