An assessment of different line-of-sight and ground velocity distributions for a comprehensive understanding of ground deformation patterns in East Jharia coalfield

Abstract

Jharia Coalfield is one of the oldest and most crucial mining regions. It faces ongoing challenges with land surface deformation due to mining operations and coal seam fires. Previous studies often overlooked the complex interplay of various LOS and ground velocities and focused mainly on vertical subsidence. This paper used the PS-InSAR for detailed ground deformation analysis of East Jharia. Ascending and descending pass time series LOS deformation datasets were obtained using advanced multi-image sparse point processing. Further, the study employed IDW interpolation in LOS velocity, followed by velocity decomposition to derive horizontal and vertical velocity components. Multi-sparse point processing and IDW interpolation enhance spatial continuity and reduce noise, ensuring the robustness of decomposed velocities. Interdependency and distribution similarity between different velocities were explored using Correlation analysis and the Global Moran's Index. Analysis revealed significant ground movement patterns with weak spatial association and underscored the necessity of both vertical and horizontal velocity for a comprehensive understanding of deformation. Subsidence smaller than −30 mm/year was observed in Sahana Pahari, northeast of Rajapur opencast mines, Jharia Main Road, and southeast of Jharia Gurudwara to Kujama Colliery at Tisra. Upliftment greater than 30 mm/year occurred in Jorapokhar, Karmik Nagar, and Kustai Basti near Ena Colliery, while lateral displacement of the same value was notable in CIMFR Colony Dhaiya, Koyla Nagar Saraidhela, Ghanoodih, Dobari, Kujama, and Barari Colliery over dumps. Correlation coefficients of 0.9165 (horizontal) and 0.7933 (vertical) revealed the dominant influence of horizontal movement on overall ground deformation. Overall, the study provided valuable insights into the spatial distribution of subsidence for 2023, highlighting the importance of different velocities in assessing and managing ground movement in mining-affected regions.