Abstract
The Longmenshan strong earthquake zone widely features "V"-shaped erosion-denudation alpine gorge landforms. The Longmenshan fault zone within the region has continuously maintained strong tectonic activity since the Quaternary, resulting in frequent collapse and landslide disasters that seriously threaten the lives and property of mountain residents. Among these, high-position landslides are characterized by strong concealment and high destructiveness. Due to their high shear outlet positions, they often possess favorable free-face conditions, making them extremely prone to high-speed, long-runout movement that can trigger sudden geological disasters of massive scale and long travel distance. This study focuses on the Bulancun landslide (soil) and Feishaguan landslide (rock) in Wenchuan County, Sichuan Province, employing "space-air-ground" collaborative monitoring technologies including multi-temporal optical satellite remote sensing, spaceborne Interferometric Synthetic Aperture Radar (InSAR), multi-temporal aerial remote sensing, Global Navigation Satellite System (GNSS), Ground-based Interferometric Synthetic Aperture Radar (GB-InSAR), and ground surveys to conduct landslide deformation monitoring and deformation mechanism analysis. A comparison of the deformation evolution characteristics between the Bulancun landslide and Feishaguan landslide reveals: ① Different deformation evolution patterns: although the deformation magnitude of the Bulancun landslide gradually increased during monitoring, its deformation rate exhibited periodic variations, with the landslide remaining in a uniform deformation stage for an extended period; whereas the Feishaguan landslide, after the 2008 earthquake triggered collapse at its leading edge, spontaneously entered an accelerated deformation stage after several years of evolution, exhibiting sudden deformation characteristics; ② Different main controlling factors of deformation: the deformation and failure of the Bulancun landslide are primarily controlled by external factors such as rainfall and human engineering activities, while those of the Feishaguan landslide are mainly driven by internal factors including earthquakes, geological structure, and topography.
Full Text
Preamble
Integrated Remote Sensing Monitoring and Deformation Mechanism Analysis of Typical High-Elevation Landslides in the Longmenshan Strong Earthquake Zone
Xincheng Wang¹,², Weile Li¹
¹State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China
²Sichuan Institute of Comprehensive Geological Survey, Chengdu 610081, China
Abstract
The Longmenshan strong earthquake zone is characterized by widespread V-shaped erosional alpine-canyon landforms. The Longmenshan fault zone has maintained strong tectonic activity since the Quaternary, resulting in frequent rockfall and landslide hazards that pose severe threats to lives and property in mountainous areas. High-elevation landslides are particularly hazardous due to their strong concealment and high destructiveness. With high shear outlets and favorable free-face conditions, they are prone to high-speed, long-runout movements, triggering sudden geological disasters of large scale and long migration distance. This study focuses on the Bulancun landslide (soil) and Feishaguan landslide (rock) in Wenchuan County, Sichuan Province, employing "space-air-ground" collaborative monitoring techniques including multi-temporal optical satellite remote sensing, spaceborne Interferometric Synthetic Aperture Radar (InSAR), multi-temporal aerial remote sensing, Global Navigation Satellite System (GNSS), Ground-based Interferometric Synthetic Aperture Radar (GB-InSAR), and field surveys to conduct landslide deformation monitoring and mechanism analysis. Comparative analysis of the deformation evolution characteristics reveals: (1) Different deformation evolution patterns: Although the Bulancun landslide exhibited progressively increasing deformation during the monitoring period, its deformation rate showed periodic variations, maintaining a long-term steady deformation stage. In contrast, after the 2008 earthquake triggered frontal collapse and sliding, the Feishaguan landslide spontaneously entered an accelerated deformation stage after several years of evolution, exhibiting sudden deformation characteristics. (2) Different dominant controlling factors: The deformation and failure of the Bulancun landslide are primarily controlled by external factors such as rainfall and human engineering activities, whereas the deformation and failure of the Feishaguan landslide are mainly driven by internal factors including earthquakes, geological structure, and topography.
Keywords: high-elevation landslide; space-air-ground collaborative monitoring; spaceborne InSAR; optical satellite remote sensing; GNSS; ground-based InSAR