Characteristics and formation controls of a representative rainfall-induced landslide cluster in Southeastern China

Rainfall-induced landslide clusters are widespread hazards in the hilly regions of southeastern China. In August 2018, an intense rainfall event triggered numerous landslides in Luhe County, Guangdong Province. Based on a detailed landslide inventory, this study analyses the geometric and kinematic characteristics of landslides and investigates their spatial patterns. Ten environmental factors were integrated using the GeoDetector model to quantify the dominant controls on landslide distribution and their interactions. The results show that the total landslide area is approximately 3 km2, with an estimated total volume of about 0.0063 km3. Most landslides exhibit heights of less than 50 m and horizontal lengths ranging from 0 to 200 m. The average height-length ratio (H/L) is 0.22, indicating relatively high mobility. Elevation and rainfall are identified as the primary controlling factors, with elevation showing the highest explanatory power. Interaction analysis reveals significant enhancement effects, particularly between elevation and rainfall, highlighting the coupled influence of topographic and triggering conditions. Furthermore, the landslides mainly occurred on granite weathering crust hillslopes within elevations of 150–600 m and slopes of 10–30°, reflecting the typical geomorphic and lithological settings of rainfall-induced landslides in southeastern China.