Comparison of L-band and X-band differential interferometric synthetic aperture radar for mine subsidence monitoring in central Utah

Differential interferometric synthetic aperture radar (DInSAR), a satellite-based remote sensing technique, has potential application for measuring mine subsidence on a regional scale with high spatial and temporal resolutions. However, the characteristics of synthetic aperture radar (SAR) data and the effectiveness of DInSAR for subsidence monitoring depend on the radar band (wavelength). This study evaluates the effectiveness of DInSAR for monitoring subsidence due to longwall mining in central Utah using L-band (24 cm wavelength) SAR data from the advanced land observing satellite (ALOS) and X-band (3 cm wavelength) SAR data from the TerraSAR-X mission. In the Wasatch Plateau region of central Utah, which is characterized by steep terrain and variable ground cover conditions, areas affected by longwall mine subsidence are identifiable using both L-band and X-band DInSAR. Generally, using L-band data, subsidence magnitudes are measurable. Compared to X-band, L-band data are less affected by signal saturation due to large deformation gradients and by temporal decorrelation due to changes in the surface conditions over time. The L-band data tend to be stable over relatively long periods (months). Short wavelength X-band data are strongly affected by signal saturation and temporal decorrelation, but regions of subsidence are typically identifiable over short periods (days). Additionally, though subsidence magnitudes are difficult to precisely measure in the central Utah region using X-band data, they can often be reasonably estimated.