MULTI-ORBIT SBAS-INSAR FOR LANDSLIDE IDENTIFICATION AND CHARACTERISTIC ANALYSIS IN THE QINGHAI-TIBET– LOESS PLATEAU TRANSITION ZONE: A CASE STUDY OF TONGREN CITY IN CHINA

Abstract

In the complex topographic transition zone between the Tibetan Plateau and the Loess Plateau, achieving accurate early identification and risk differentiation of landslide hazards remains a significant challenge for geological disaster prevention and control. This study, focusing on Tongren City, Qinghai Province, as a typical case, explores an integrated SBAS-InSAR approach combining ascending and descending SAR imagery to overcome the geometric occlusion and deformation direction misinterpretation inherent in single-track monitoring. By processing time-series data from 2020 to 2024, we successfully derived a two-dimensional deformation field for the study area and, combined with field validation, accurately identified 23 landslide hazards. The study found that 16 of these hazards directly threaten key vulnerable elements such as roads and villages, requiring urgent risk management. Furthermore, this research elucidates the formation mechanisms of two representative landslide types: The Jiamao ancient landslide, which exhibits a "hydrologically driven, multi-phase reactivation" pattern with deformation strongly correlated with rainfall cycles, and the Womao potential landslide, which shows ‘slow-creep’ under a combined mechanism of "human disturbance and freeze-thaw driving," with substantial cumulative deformation. This study not only verifies the applicability of multi-track InSAR technology in plateau transition regions but also provides direct evidence for precise landslide risk management and sciencebased decision-making at the local level.