Landslide Hazard Assessment Based on GIS: A Case Study of a Hydropower Station Area in China

Geographical information systems (GIS) are powerful for spatial analysis, and the analytic hierarchy process (AHP) has certain advantages in multi-index integrated evaluation. The combination of GIS with AHP provides an effective measure for hazard assessment of landslides. Based on detailed field observations and analysis of the factors influencing landslides in the region of the Lianlu Hydropower Station on the Tao River in Gansu province, northwestern China, an aggregate evaluation index system was set up including various factors such as density of faults, relative height of hills, gradient of slopes, land usage and engineering activity. The weight of each factor was determined by AHP. Supported by GIS, using the grid of 1 km² as the evaluation cell, thematic layers for each factor were established and superimposed. In the end, the study area was divided into four types of risk regions: high-hazard, medium-hazard, low-hazard and non-hazard regions. The results coincide well with the actual hazard distribution observed, and show that the coupled method has a preferable applying foreground for landslide hazard assessment.