Study on land subsidence characteristics and deformation evolution mechanism in Caofeidian New Area, Bohai Bay

Land subsidence caused by natural or human factors is a very serious geological hazard. Ground buildings and environments are affected by land subsidence in some large cities and new economic development zones worldwide. The most direct cause of land subsidence are complex geological conditions and excessive mining of underground resources. It will have great significance for disaster prevention and controlling to understand the formation mechanism and evolution rule of land subsidence. In this research, the small baseline subset-interferometric synthetic aperture radar (SBAS-InSAR) was used to analyse land subsidence of Caofeidian in Bohai Bay, which could monitor the surface deformation velocity and displacement spatiotemporal evolution through the acquired SAR image dataset. A total of 43 sentinel images from January 2019 to December 2021 were used to calculate the time series of surface deformations. The results showed that there was an obvious subsidence deformation in the central and southern parts of Caofeidian, while the abnormal local subsidence was mainly reflected in the northern part. Geological conditions, groundwater exploitation and engineering disturbance were the main influencing factors of land subsidence. Combining the evolution results with the geological conditions, the surface deformation mechanism and subsidence mode in different regions of Caofeidian were concluded. Subsequently, the environmental effects and potential hazards were analysed. Our research proposed and established sequences of spatiotemporal evolutionary, analysis methods on mechanism and evolution of land subsidence, which is of great significance for regional disaster control.