Monitoring surface deformation dynamics in the mining subsidence area using LT-1 InSAR interferometry: A case study of Datong, China

Abstract

Monitoring of mining-induced subsidence dynamics enables to the exploration and analysis of changes in the direction of surface deformation caused by the extraction of underground resources. Both human activities and geological environments affect these changes to a large extent. LuTan-1 (LT-1) satellite as the first SAR mission with L-band bistatic spaceborne in China, provides continuous imagery for analyzing surface deformations through differential SAR interferometry, offering valuable velocity results using stacking techniques. The results of the subsidence bowl obtained from LT-1 closely align with those from Sentinel-1 in the almost same period in Datong, China. Furthermore, we validated the DInSAR results of LT-1 and Sentinel-1 using continuous GNSS data from the corresponding time frames. Notably, we observed a significant improvement in the quality and accuracy of LT-1 datasets due to the in-orbit performance test. Finally, we explored the surface deformation dynamics pertinent to mining activities using DInSAR results obtained from four different time periods. These results revealed substantial changes on the shape and spatial location of the subsidence bowls over time. This indicates a maximum horizontal displacement in the directional change of approximate 1.429 km and an average face advance rate between 0.724 and 6.355 m/day within about a one-year time period. Lastly, velocity and accumulated displacement gradient maps, derived from stacking results, were overlaid to the distribution of critical infrastructures in the study areas to assess their exposure to mining subsidence, and a validation process was carried out using GF-7 optical images. This study emphasizes the potential of LT-1 to monitor mining subsidence dynamics and its capability for joint analysis with the exposure of critical infrastructures.

Keywords

• Mining subsidence
• LT-1
• DInSAR
• Stacking
• Face advance rate
• Exposure