Investigating the first case of permafrost degraded subsidence in Lahaul & Spiti region of Tethyan Himalayas

This study investigates the first case of permafrost thaw-induced subsidence in the Lindur Village of Lahaul & Spiti district of Himachal Pradesh using MT-InSAR method. The authors of the study used 15 Sentinel-1 single-look complex images acquired from April 2022 to September 2022 along the ascending orbit track and used the SBAS technique to monitor the subsidence in the village.

The results revealed significant land subsidence rates ranging from 7.9 to −6.8 cm/year. The cumulative land subsidence of 16 cm was observed over the northeast direction of the village. The analysis of historical temperature and precipitation data from 1950 to 2024 shows a significant rise in temperature at a rate of 0.02 °C/year and a shift in precipitation pattern over the village. From the field observations, the study found that the local geology and existing rock glaciers exacerbate the rate of subsidence leading to the development of cracks in the region.