Inventory, Susceptibility Assessment, and Morphometric Characteristics of Landslides in Lanping County, Yunnan, China

Lanping County, located on the southeastern margin of the Qinghai–Tibet Plateau, is a key component of the “Three Parallel Rivers of Yunnan” World Natural Heritage Site, where widespread landslides pose significant threats to local communities. However, landslide spatial patterns and susceptibility assessments in this county remain poorly understood. This study compiled a detailed landslide inventory through high-resolution remote sensing interpretation, employing the certainty factor (CF) model to map landslide susceptibility and analyze spatial distribution patterns. The results show that a total of 1792 landslides were identified, predominantly distributed at elevations of 1500–3000 m, on slopes of 15–45° with aspects of 180–210°, and in areas with topographic relief of 150–450 m and annual rainfall >925 mm. Most landslides are located within 750 m of rivers, 4000 m of faults, and 1500 m of roads. The Jurassic (J) stratigraphic unit exhibited the highest landslide area density (LAD = 0.32). Morphometric analysis revealed that most landslides display longitudinal morphologies, with heights of 50–265 m and travel distances of 25–200 m, exhibiting allometric scaling relationships with volume. The mean reach angle of 31.8° was higher than that of Dongchuan District (29°). Susceptibility mapping indicated that the very low, low, moderate, high, and very high susceptibility zones account for 12.23%, 26.46%, 26.97%, 19.98%, and 14.36% of the study area, respectively. The high and very high susceptibility zones together comprise 34.34%, concentrated along the Lancang River main stem and its tributaries. These findings enhance understanding of landslide spatial distribution and morphological characteristics along the southeastern margin of the Qinghai–Tibet Plateau, providing a scientific basis for regional landslide management and sustainable land-use planning.