[Objective] The rainfall intensity-duration threshold of rainfall-induced landslides in Huangshan City

Anhui Province was studied in order to provide technical support for detailed landslide early warning in all districts and counties of Huangshan City. [Methods] Rainfall duration of induced landslides was determined by comparing the effective rainfall before landslides at historical landslide points

and by using corresponding rainfall data in Huangshan City from 2004 to 2019. The rainfall intensity-duration (I-D) threshold curve for each district and county was established based on the empirical threshold Caine model. Considering the applicability of I-D curve in disaster early warning

and taking the landslide point in Shexian County as an example

the rainfall events that induced landslides in Shexian County were divided into the small and moderate rain group

the heavy rain group

and the heavy rain or above group according to the rain intensity standard of the meteorological forecast. The I-D threshold of combined rainfall in Shexian County was established according to the grouping classification of rain intensity. [Results] Most of the rainfall-induced landslides in Huangshan City were induced by long and medium duration rainfall. The complex I-D threshold could better reflect the inducing effect of various rainfall conditions on landslides

and this threshold could be directly used for early warning of landslides using precipitation forecasts. [Conclusion] I-D threshold has strong regional applicability

and the landslide rainfall threshold grouped by rainfall intensity according to precipitation forecasts is suitable for the construction of a landslide early warning system in this region.