Interpreting land subsidence impacts due to groundwater depletion using remote sensing-based GRACE gravity anomaly and DInSAR technique: a study on north-western parts of India

Extraction of water reserve is at risk, especially at several locations of north-western India due to tremendous growth in populations and excessive use of water over the decade. It has been evident through this study that several regions in Punjab such as Dera Bassi, Landran, Singhpura, and Ambala in Haryana are facing constant depletion of groundwater at the rate of 46.26 cm/year, 49.16 cm/year, 120.77 cm/year and 237.69 cm/year, respectively, during 2005-2018. Whereas, depleting trends have also been analysed with derived GRACE gravity anomaly of 12.65 cm/year at respective locations. Although these areas lie in arid to semiarid zone, with moderate precipitation in the monsoon month of June-August, it does not meet the requirement of recharging the aquifer to the previous level, hence causing land deformation, which is mostly witnessing tensional, compressional and shear cracks with vertical, horizontal and diagonal orientation in nature, which further deliberated using conventional DInSAR. To identify the deformed hotspots in the affected areas, DInSAR was performed using remotely sensed Sentinal-1 SAR sensor. Additionally, to interpret the seismic consequences around the study area, pre-seismic data were examined and categorised medium intensity (in between 4.5 and 4.9 mb) earthquake, which did not affect the structures. Therefore, from the study, it was agreeable to manifest that the deformation which took place in the area is due to massive long-term extraction of groundwater.