Radar Interferometry for Mining Subsidence Monitoring

Coal mining activities all over the world often introduce serious environmental impact to the local regions, such as the occurrence of land subsidence. Conventional subsidence monitoring is done by precision leveling and GPS surveying. However, recent studies show that differential interferometric synthetic aperture radar (DInSAR) is capable of monitoring land subsidence at sub-cm accuracy. In this paper, DInSAR was applied to detect the land subsidence in the Northern China Plain (NCP). This region is well known for being suffering from the mine subsidence. In this study, two-pass DInSAR method was used with a Shuttle Radar Topography Mission (SRTM) C-Band digital elevation model (DEM). Twenty JERS-1 L-band SAR images were used. Based on time-spans and data quality, mainly the atmospheric effect and decorrelation, 4 pairs were selected for demonstrating the land subsidence monitoring. The results revealed the mine subsidence maps which had the different patterns and characteristics than the results shown in our previous studies for the underground mining subsidence in Australia. This is due to the different mining techniques utilised at the two study sites. The results showed that land subsidence was evident at the test site, and more than ten subsidence bowls were found within an area of 8.8 x 23 kilometre square. The maximal subsidence rate of 28 cm over 44 days was found in the study.