Deformation, structure and potential hazard of a landslide based on InSAR in Banbar county, Xizang (Tibet)

Abstract

The Tibetan Plateau is characterized by complex geological conditions and a relatively fragile ecological environment. In recent years, there has been continuous development and increased human activity in the Tibetan Plateau region, leading to a rising risk of landslides. The landslide in Banbar County, Xizang (Tibet), have been perturbed by ongoing disturbances from human engineering activities, making it susceptible to instability and displaying distinct features. In this study, small baseline subset synthetic aperture radar interferometry (SBAS-InSAR) technology is used to obtain the Line of Sight (LOS) deformation velocity field in the study area, and then the slope-orientation deformation field of the landslide is obtained according to the spatial geometric relationship between the satellite's LOS direction and the landslide. Subsequently, the landslide thickness is inverted by applying the mass conservation criterion. The results show that the movement area of the landslide is about 6.57×10⁴ m², and the landslide volume is about 1.45×10⁶ m³. The maximum estimated thickness and average thickness of the landslide are 39 m and 22 m, respectively. The thickness estimation results align with the findings from on-site investigation, indicating the applicability of this method to large-scale earth slides. The deformation rate of the landslide exhibits a notable correlation with temperature variations, with rainfall playing a supportive role in the deformation process and displaying a certain lag. Human activities exert the most substantial influence on the spatial heterogeneity of landslide deformation, leading to the direct impact of several prominent deformation areas due to human interventions. Simultaneously, utilizing the long short-term memory (LSTM) model to predict landslide displacement, and the forecast results demonstrate the effectiveness of the LSTM model in predicting landslides that are in a continuous development and movement phase. The landslide is still active, and based on the spatial heterogeneity of landslide deformation, new recommendations have been proposed for the future management of the landslide in order to mitigate potential hazards associated with landslide instability.