Study on ground deformation in Kathmandu valley using C-band sentinel-1A synthetic aperture radar (SAR) satellite images

Interferometric synthetic aperture radar (InSAR) is a prominent and widely used remote sensing method used for accurate surface deformation across large areas. We applied this technique to study the subsidence and upliftment of the ground surface in Kathmandu Valley in the years between 2019 and 2023 AD. C-band (4 GHz-8 GHz) Sentinel-1A images from 2019 to 2023 were employed in this study to investigate the status of ground deformation. This study highlights ground upliftment in major parts of the valley in the year 2022 and 2023 where as the valley experienced major subsidence during the year 2020 to 2022. In this study we also found that the major subsidence were found in the central north region and south eastern part of the valley. But in the years between 2022 and 2023 major upliftment was found in the northern part of the valley. In general the study shows major deformation over a four-year time interval which may have occurred due to the seismic movement or groundwater depletion.