Precipitation Threshold for Rainfall-Type Landslides in the Qinba Mountains Area,Sichuan Province,China
The Qinba Mountains area in Sichuan province,China,has been known for high incidences of landslides partly due to complex local terrain and frequent microclimate extremes,but precipitation is certainly one of the main natural factors causing landslides.Although the existing regional landslide warning system provides regular monitoring services,there is still room for improvement in its accuracy.In this study,1850 landslide events and simultaneous hourly precipitation data from 2000-2020 were collected and regressively analyzed to identify the key rainfall patterns governing landslide occurrences;an optimal threshold curve of precipitation was determined using combined indicators such as confusion matrix and skill scores.(1)The optimal precipitation threshold curve for inducing landslides in the Qinba Mountains area was determined by fitting,and validated by the case of landslide forecast in 2021,with a prediction accuracy of 87.72％.(2)By applying the optimal precipitation threshold curve to landslide hazard mapping through catalog data of field survey,it was found that 51.46％of landslides were in high-risk zones(classes 4 and 5)and 91.23％were in medium to high-risk zones(classes 3 to 5),justifying the effectiveness of the threshold curve for spatial prediction.This study provides important scientific references for the optimization of the current landslide early warning system,improving the efficiency of disaster management,and supporting landslide disaster prevention and mitigation.
rainfall-induced landslideprecipitation thresholdlandslide early warningthe Qinba Mountains area
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