Investigating Jharia Coalfields using SAR Interferometry

Coal mining gives rise to significant ecological and environmental challenges, rendering it a potential detriment unless effectively managed. The primary aim of this research is to investigate the spatio-temporal deformation resulting from mining activities, particularly subsidence, employing multi-temporal SAR interferometry (MT-InSAR). We analysed Jharia coalfields (Dhanbad, India) by utilising a dataset comprising 71 Sentinel-1A acquisitions spanning the timeframe from January 2021 to July 2023. As a result, the MT-InSAR processing produced a 1D line-of-sight (LOS) velocity ranging from 10 mm/year to -19 mm/year. Five zones (A1–A5) based on high negative 1D LOS velocity are selected for time-series analysis, and all zones showed a decreasing trend of time-series as a proxy of subsidence. We attempted the geophysical investigation based on geological settings and the presence of coal fires in this region. It has been found that the prime reason for subsidence in this region is coal fire, which is also following a fault line. This study shows the need for continuous monitoring of such unstable regions to avoid the possibility of serious disasters.