Slope Stability Analysis in Nainital Town Using PS and QPS Insar Technique

Abstract

The purpose of this study was to analyze the slope stability in Nainital town using Persistent Scatterer (PS) and Quasi Persistent Scatterer (QPS) Interferometric Synthetic Aperture Radar (InSAR) techniques. C- Band radar imaging satellite Sentinel 1A and 1B SAR dataset is used for the PS and QPS processing. Mean Velocity maps have been produced for the study period. Time series plots have been also generated for the few selected points to determine the temporal behaviour of movement in satellite Line of Sight (LoS) direction. Both PS and QPS results revelled that at the NW and SW slopes, areas in vicinity to Naini Lake have shown no movement and are stable during the study period of one and half year. At the N-NE slopes many locations at snow view point and Sher- ka- Danda hill slopes noticeable movement has been detected during the study period. Snow view peak are identified as most unstable and mean velocity is measured from −25 mm to −30 mm/year in satellite Line of Sight (LoS) direction. Slow slope movement has been detected at the dense urbanized area of Lower Mall Road near Naini Lake. On the Southern slopes, velocity has been estimated at Baliya Nala Landslide area for few identified points. The study clearly illustrates the usefulness of PS and QPS approaches for slope stability analysis and for estimation of slope movement in Nainital town.