Mechanism analysis of winter landslides triggered by the “butterfly swarm effect” in the Wumeng Mountainous Region from the landslide in Jinping Village，Junlian County，Sichuan Province
(1. Key Laboratory of Transportation Tunnel Engineering of Ministry of Education, Southwest Jiaotong University, Chengdu, Sichuan 610031, China; 2. The 1st Geological Brigade of Sichuan, Chengdu, Sichuan 610071, China; 3. Sichuan Institute of Geological Engineering Investigation Group Co., Ltd., Chengdu, Sichuan 610071, China; 4. Technology Innovation Center
for Geological Disaster Prevention and Ecological Restoration in Western China, Ministry of Natural Resources,
Chengdu, Sichuan 610071, China; 5. The 12th Geological Brigade of Sichuan, Yibin, Sichuan 644002, China)
Abstract：On February 8, 2025, a significant landslide occurred in Jinping Village, Mu′ai Town, Junlian County, Yibin City, Sichuan Province, under winter conditions without heavy rainfall or seismic activity. This disaster resulted in 10 fatalities and 19 missing persons, igniting widespread public discourse regarding the formation mechanisms of this landslide and the potential for winter to be a high-incidence period for landslides in the Wumeng Mountainous Region. In response, a multi-source data fusion analysis method was employed, integrating field geological surveys, historical disaster investigations, airborne LiDAR terrain interpretation, time series InSAR surface deformation monitoring, and discrete element numerical simulation techniques. The study comprehensively examined the landslide′s causes from various aspects, including terrain and geomorphological conditions, geological and lithological characteristics, rock structure features, historical disaster context, rainfall, earthquakes, and the “chimney effect”. Furthermore, the post-instability movement process of the landslide was simulated. Through comparative analysis of three typical landslide cases—Jinping Village in Junlian County, Liangshui Village in Zhenxiong County, and Zhaojiagou in Zhenxiong County—the research discussed the mechanisms of winter landslides induced by the “butterfly swarm effect” in the Wumeng Mountainous Region and proposed preventive recommendations. The findings indicate that continuous rainfall is the direct trigger of the Jinping Village landslide, with the landslide process categorized into five distinct stages: initiation, shearing and falling, landing and scraping, oblique throwing, and scraping and accumulation. Continuous rainfall or rain-snow events are critical triggering factors for winter landslides in the Wumeng Mountainous Region. Under the synergistic effects of steep terrain, landslide-prone strata, and unfavorable rock mass structures, a“butterfly swarm effect”emerged, where multiple factors interacted through nonlinear superposition and cascading reactions, ultimately leading to macro-events (landslide disasters) that far exceeded the impacts of individual factors (precipitation). This study serves as a significant reference for further investigation into the Jinping Village landslide in Junlian County and winter landslides in the Wumeng Mountainous Region.
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2025, Vol. 44 
