Fig. 3

Mean vertical deformation rates in Zhengzhou from January 2018 to December 2022. Positive values (dark blue) represent uplift, and negative values (warm colours) represent subsidence. The red dashed polygons indicate three major subsidence zones: the northern region of Zhongmu (Sub_zone1), the northwest of Xingyang (Sub_zone2), and the western region of Gongyi (Sub_zone3). The black dashed polygons indicate two major uplift zones: the central city district (Upl_zone1) and Xinzheng Airport (Upl_zone2). This figure was generated in ArcGIS 10.6 software (https://www.esri.com).