Multi-Source Information Fusion and Dynamic Failure Prediction of Post-Earthquake Landslides: A Case Study of Hejiapo in the Wenchuan Earthquake-Affected Area

Strong earthquake-induced geological hazards are characterized by extensive affected areas, severe consequences, and significant long-term cascading effects, posing serious threats to human life, property safety, and sustainable socio-economic development in earthquake-affected regions. Existing landslide susceptibility assessments mainly focus on regional-scale predictions, while slope-scale co-seismic responses and dynamic hazard management remain insufficiently studied. This study focuses on Hejiapo, Longchi Town, Dujiangyan City, located in the strong earthquake-affected area of the Wenchuan earthquake. A comprehensive approach integrating multi-temporal remote sensing interpretation, field geological surveys, topographic mapping, statistical modeling, and numerical simulation was employed to identify major controlling factors and evaluate landslide susceptibility. Six conditioning factors were selected, and an area-based Information Value (IV) model was applied for landslide susceptibility assessment. Based on the susceptibility assessment results and field investigation, potential unstable zones were identified. Numerical simulations were further conducted to analyze the potential failure modes, movement processes, and affected areas of these unstable zones. The results indicate that: (1) A total of 28 post-earthquake landslides were identified, with a cumulative area of 364,932 m2, accounting for 19.64% of the study area. These landslides exhibit characteristics of being spatially clustered and having relatively small individual scales and a single dominant failure type. (2) The susceptibility assessment results show that very-high- and high-susceptibility zones are negatively correlated with road distance and fault distance, and are mainly distributed along both sides of the roads and steep ridge areas. (3) Two potential unstable zones were delineated, covering a total area of approximately 0.051 km2, mainly distributed along the southwestern ridges of Hejiapo. (4) The identified unstable zones have the potential to generate high-elevation landslide debris flow hazards. Numerical simulations reveal that the debris materials would mainly migrate downward along slope channels. The channel–road intersections and channel outlets are identified as the principal potential impact zones, which should be considered a priority area for geological hazard prevention. This study provides a methodological framework beyond the traditional static approach of “hazard investigation” by establishing a dynamic risk management concept (susceptibility zones–risk points–potential disaster chains). The proposed framework enhances the understanding of the entire disaster prevention and mitigation process and provides scientific support for precise regional hazard mitigation planning and territorial spatial management.