remote sensing Article Detecting and Analyzing the Evolution of Subsidence Due to Coal Fires in Jharia Coalfield, India Using Sentinel-1 SAR Data Moidu Jameela Riyas 1, Tajdarul Hassan Syed 2,* , Hrishikesh Kumar 3 and Claudia Kuenzer 4,5 1 Department of Applied Geology, Indian Institute of Technology (Indian School of Mines), Dhanbad 826004, India;
[email protected] 2 Department of Earth Sciences, Indian Institute of Technology Kanpur, Kanpur 208016, India 3 Geosciences Division, ISRO—Space Application Center, Ahmedabad 380015, India;
[email protected] 4 Earth Observation Center (EOC), German Aerospace Center (DLR), 82234 Oberpfaffenhofen, Germany;
[email protected] 5 Chair of Remote Sensing, Institute of Geography and Geology, University of Wuerzburg, 97074 Wuerzburg, Germany * Correspondence:
[email protected] Abstract: Public safety and socio-economic development of the Jharia coalfield (JCF) in India is criti- cally dependent on precise monitoring and comprehensive understanding of coal fires, which have been burning underneath for more than a century. This study utilizes New-Small BAseline Subset (N-SBAS) technique to compute surface deformation time series for 2017–2020 to characterize the spatiotemporal dynamics of coal fires in JCF. The line-of-sight (LOS) surface deformation estimated from ascending and descending Sentinel-1 SAR data are subsequently decomposed to derive precise vertical subsidence estimates. The most prominent subsidence (~22 cm) is observed in Kusunda colliery. The subsidence regions also correspond well with the Landsat-8 based thermal anomaly map and field evidence. Subsequently, the vertical surface deformation time-series is analyzed to Citation: Riyas, M.J.; Syed, T.H.; characterize temporal variations within the 9.5 km2 area of coal fires.