Monitoring Regional Surface Subsidence of Ningdong Coal Base by DinSAR

The exploitation of Ningdong coal base has become an important engine for industrial economic development in Ningxia. Surface subsidence, which caused by coal mining has become the main geological environmental problem in the area. This study monitored regional surface subsidence characteristics of Ningdong coal base by utilizing Differential Interferometry Synthetic Aperture Radar (DinSAR) and Sentinel-1A dataset from 2015 to 2019. The results indicated that the characteristics of subsidence vary widely in different regions and years, subsidence in the north is larger than that in the south, which maximum reached 0.13 m. In the past four years, the subsidence from 2015 to 2016 is most serious and however its from 2016 to 2017 is lest. During 2015～2019, the area with subsidence value more than 0.1 m were 578 km². The subsidence area is consistent with the mining activity area, which means that the surface subsidence is mainly caused by coal mining. Other slight surface subsidence, on the one hand, could caused by coherent distortion of radar image and be related to the surface deformation such as wind-sand erosion on the other hand. DinSAR technique has distinct advantage in monitoring large-scale land subsidence, but there is a loss of coherent phenomenon due to the long time baseline.