Landslide risk assessment methods and flow on a large scale—A case study of loess landslides risk assessment in Yan'an urban districts, Shaanxi, China

How to assess the landslides risks on a large scale, which is 1∶5000~1∶25000 and applies for the zoning area tens to hundreds of square kilometers, is a technique problem that deserves to be studied. Using the traditional methods that assess the risk by calculating value for each raster grid based on GIS always can not get the zoning results which meet the accuracy scale required. This paper introduced a new method. Firstly, it identifies the susceptible areas by comprehensively utilizing the high resolution DEM and Quick Bird data. It plots the hazards boundary and interprets the elements at risk on the remote sense image. Secondly, it checks, verifies, or cancels the above results through the field investigation. And finally, it makes the end-produced zoning maps which reach a relative high accuracy. From practical experiences it can see that it is a valid method to do the large scale landslides risk assessment.