A method of early warning on rainfall-induced landslide risk probability based on hazard zoning: a case study on the rainfall-induced landslide of Miyi County, Sichuan, China

Rainfall-induced landslide early warning is broadly conducted in the world, but still little work has been done for small-scale risk. This paper starts from the common definition of risk, investigated the geo-hazard of Miyi County, Sichuan province, China. The first step is landslide zoning by contributing weight method after obtaining the main factors that cause landslide with inversion, then the second step is vulnerability zoning after analyzing the main disaster-bearing objects and convert their density from administrative regionalism to 1km×1km grid. After these two steps the risk zoning is achieved. The third step is get the rainfall threshold value according to daily rainfall modeling, by analyzing the relationship between daily precipitation in the past 5 years and 172 pieces of geo-hazard records. Trough overlaying landslide spatial probability with precipitation time probability, regional rainfall-induced landslide probability is obtained. Early warning work can be carried out with the help of risk zoning result.