Spatial variation of three-dimensional deformation: a case study in the north-eastern Beijing plain, China.

Land subsidence is a serious geo-hazard in Beijing Plain, which has threatened the safety of the operation of the metropolis. This study focuses on the land subsidence in the Chaobai River alluvial fan, where is the main groundwater supply region. The vertical and the East-West deformation from June 2015 to December 2017 was derived based on the SAR imaging geometry deduction. Then, the spatial variation characteristics of the deformation were analysed and the relations with the impact factors were carried out. Results show that the nugget effect (i.e., random to total spatial variance ratio) values of the vertical and the East-West deformation at regional scale were 13 % and 49 %, respectively. This indicates that the distribution of the vertical deformation is dominated by regional influencing factors, while both regional and local-scale impact factors are important for the distribution of the East–West deformation. In the southern part of the study area, the extraction of groundwater is the dominant factor affecting the spatial distribution of the vertical displacement, while the dominant factor of East-West deformation is not obvious. This study can enrich the understanding of land subsidence distribution and will help us better understand the causes of land subsidence. [ABSTRACT FROM AUTHOR]