Monitoring and Understanding Land Subsidence in Joshimath: An InSAR and Ground-based Study

Joshimath - a small hilly village in Uttarakhand, India is facing severe land subsidence. More than 600 houses and roads and roads have developed cracks, and the government has ordered the immediate evacuation of families in the area.

Joshimath has seen significant urbanization in recent years due to its strategic location and the increasing popularity of tourism and adventure sports in the region. There has been a growing demand for infrastructure and services to accommodate the influx of tourists, leading to the development of new hotels, resorts, and other facilities. Over the years, several hydroelectric, road, and tunnel construction projects have also been undertaken in the region. 

In order to better understand and mitigate the risk of landslides in this area, it is important to implement a robust monitoring system. Interferometric Synthetic Aperture Radar (InSAR) is a remote sensing technique that has been used successfully in the past to monitor landslides and other ground deformation events. In this study, we used InSAR to monitor land subsidence in Joshimath over a period of 20 months (May 2021 - Jan 2023). We collected radar data from Sentinel-1 and performed PSInSAR analysis. Our preliminary analysis revealed continuous deformation of the order of 4cm/year in the region. Specific locations are selected for further detailed analysis, and field work is being carried out to provide additional information such as effects of subsidence and vulnerability of the area. This information can be used to develop a comprehensive understanding of the subsidence problem in Joshimath.