Abstract:Based on a new geographic information systems (GIS) grid-based 3D deterministic model and taking the slope unit as the study object,the landslide hazard is mapped by the index of the 3D safety factor. Assuming the initial slip as the lower part of an ellipsoid,the 3D critical slip surface in the 3D slope stability analysis is obtained by means of a minimization of the 3D safety factor using the Monte-Carlo random simulation. All the calculations are implemented by a computational program 3DSLOPEGIS in which a GIS component is used for fulfilling the GIS spatial analysis function.