Hydrological-driven landslide in northwestern China measured by InSAR time series analysis

Abstract

[EN] The Lashagou landslide group is located in the transition zone between the Tibetan Plateau and Loess Plateau and is a typical shallow loess landslide group. Precipitation is a major hydrologic trigger for landslides in the northwestern China. Monitoring landslide movement constitutes a critical and requisite component of landslide hazard mitigation. Multi-track InSAR time series analysis can extract the 3D displacement of landslide, provide an indication of landslide occurrence and extent. In addition, quantifying the interaction between precipitation and landslide initiation and mobility to empirically determine the precipitation threshold associated with landslide movement is crucial for mitigating landslide hazards. In this paper, we highlight the results on mapping landslides over the state of Lashagou landslide group. The deformation rate and time series deformation of the Lashagou landslide group in the line-of-sight (LOS) direction from February 2020 to February 2021 were calculated using ascending and descending Sentinel-1A and Stanford Method for Persistent Scatterers (StaMPS) techniques. Besides, we obtained the two-dimensional deformation of the Lashagou landslide group by combining the slip geometr, LOS deformation, and SAR satellite imaging geometry. The results show that Lashagou landslide group is in the creep deformation stage. We compared the time series deformation of the extracted InSAR with that of the projected GNSS, and find that the measured values of InSAR and GNSS are highly similar in amplitude and deformation trend. In addition, the safety operation of G310 highway under the Lashagou landslide group was evaluated according to the observed deformation. We conclude that concentrated continuous rainfall is the main driver of landslide displacement, and that satellite observations of landslide movement and analysis of hydrological variables have improved our understanding of landslide mechanisms.