Rainfall early warning threshold and its spatial distribution of rainfall-induced landslides in China

In order to investigate the spatial distribution of early warning threshold for landslide induced by rainfall in China, the literatures about rainfall thresholds of landslides in China in recent 20 years are selected. Statistical analysis and visualization methods were employed to systematically analyze the research progress of rainfall early warning thresholds at various scales. Taking the typical rainfall intensity-duration (I-D) threshold model as the research object, combined with the geographical characteristics of China and the average annual rainfall of 20 years, the spatial distribution of early warning thresholds for rainfall-induced landslide in China is depicted. The results show that the inspired rain intensity coefficient α of the rainfall threshold (I-D curve) in China roughly increases gradually with the decrease of topography. Moreover, under consistent annual rainfall conditions, the scalar index β exhibits regular changes corresponding to variations in terrain. Topography and rainfall are the two main factors strongly associated with the rainfall threshold. This research establishes a clear framework for studying the early warning thresholds for rainfall-induced landslides in China and holds significant scientific implications for developing more effective rainfall threshold models.