Monitoring surface subsidence in the Binchang mining area using small baseline subset differential interferometric synthetic aperture radar with Sentinel-1A data

Abstract

Surface subsidence caused by mining is difficult to monitor. Traditional field measurements are time-consuming and labor intensive. Small baseline subset (SBAS) technique is a long-term sequence method based on the principles of radar interferometry that can be used to effectively survey small ground surface deformations. This technique has been successfully applied to urban subsidence in previous studies, but it has rarely been used to study subsidence in mining areas. A total of 62 Sentinel-1A images taken from March 2017 to March 2019 were used to analyze the surface subsidence of the Binchang mining area in Shaanxi Province, China. The accuracy was evaluated using the measured field data from six ground control points for eight different months. The root-mean-square-error and correlation coefficient (r) for the data obtained using SBAS and field measurements were 2.27 cm and 0.944, respectively. We examined 12 main subsidence areas with a mean subsidence rate of −11.88 cm / year, where the maximum cumulative subsidence of a single deformation point reached 83.46 cm. The subsidence areas also had differences in spatial distribution and subsidence formation processes. The geological and groundwater conditions were the same for all areas of the study, and mining in the surrounding coal mines was the main cause of surface subsidence. We demonstrate that SBAS differential interferometric synthetic aperture radar technique can be used as an effective method for the long-term monitoring of mining deformation.