Spatial Distribution and Factors Influencing Clustered Landslides Triggered by Typhoon Rainstorms in Western Guangdong

Abstract

In the context of global climate change, clustered shallow landslides triggered by extreme rainfall from typhoons have become among the most destructive geological disasters in the mountainous regions along the southeastern coast of China. However, a systematic understanding of the spatial clustering patterns of landslides and multifactorial nonlinear disaster mechanisms under complex topographic and geological conditions is lacking. This study focuses on clustered shallow landslides induced by Typhoon Sanba in the mountainous regions of western Guangdong in 2023. On the basis of high-resolution remote sensing imagery from Planet, a detailed landslide inventory is compiled. Combined with the use of an explainable machine learning framework, this study reveals the spatial distribution characteristics of landslides and multifactor synergistic driving mechanisms. The results indicate that the clustered landslides caused by Typhoon Sanba exhibit significant spatial clustering, with landslides concentrated primarily in areas containing weathered granite in low- to mid-elevation mountains affected by heavy rainfall, as well as in regions characterized by thick colluvial deposits and steep slopes. Rainfall is the primary factor that controls landslide development and exerts a distinct nonlinear threshold effect. Slope, thickness, and lithology amplify spatial variations in landslide development by jointly regulating the slope material structure and stability. Synergistic enhancement is observed between extreme rainfall and conditions such as weathered granite, thick colluvial deposits, and steep slopes, indicating that typhoon-induced clustered shallow landslides result from the combined coupling of extreme hydrological conditions and the regional topographic and geological environment. These findings provide a scientific basis for assessing typhoon and torrential rain disaster risks and for ensuring disaster prevention and mitigation in this region.