Abstract:

Landslide, which is mainly due to rainfalls, is one of the most harmful geological disasters. The key issue of the early warning and forecast of landslide is to determinate the landslide hazard formative critical rainfall with the traditional method of statistical analyses between disaster and rainfalls. However, these methods always ignore some factors affecting landslide disaster including vegetation cover and geological condition and determinate the landslide hazardformative critical rainfall only standing for a value for regional average but not for a concrete landslide point. Soil erosion caused by rainfall would lead to landslides when it reaches a certain intensity. Therefore, it is feasibility to determinate of landslide hazard formative critical rainfall on the basis of soil erosion model. In view of the problems in existing researches and the hazardformative mechanism of RainSoil erosionLandslides, a novel method based on soil erosion model was tried out in Zigui county of hubei province with the following steps. Firstly, various factors including rainfall erosivity, soil erodibility, topographic conditions, such as slope length and slope gradient, vegetation cover and land use types are calculated by employing remotely sensed data, geographic information data and meteorological rainfall data. Secondly, several landslide cases were analyzed using USLE (Universal Soil Loss Equation) soil erosion model to determinate the soil erosion intensity for landslide critical. Thirdly, the hazardformative critical rainfall amount of the landslide warning sites was calculated on the basis of the relationship between the rainfall erosivity and rainfall amounts. Finally, those determined values of landslide hazardformative critical rainfall were accurately tested. Conclusively, the method based on soil erosion model is feasible to determinate landslide hazardformative critical rainfall. The proposed method shows a clear physical meaning with the considerations of various affecting factors including rainfall, vegetation cover and geological condition for landslide and easy implementation in practical work, thus has a highly practical value in the landslide early warning and forecast.