Spatial distribution and susceptibility zoning of geohazards along the Silk Road, Xian-Lanzhou

The region between Xi’an and Lanzhou is the first and most important part of the so-called Silk Road in China. However, this section is highly susceptible to geohazards, including landslides, debris flows, etc., as a result of complex geological formations, steep landforms, seasonal heavy rainfall, and intensive anthropogenic activity that characterize this region. These geohazards have resulted in significant damage to the local infrastructure and economy and are becoming increasingly frequent with time. To identify the distribution of characteristics of geohazards and susceptibility zoning in this region, a frequency analysis and logistic analysis were used to study the spatial distribution of geohazards. The key factors of surface topography and geology associated with geohazards were considered, including slope gradient, height differential, profile curvature, slope aspect, and rock hardness. First, the distribution and frequency of geohazards were discussed in relation to the five factors. Second, each factor’s influence was evaluated by logistic regression and the relative importance of each of the variables was discussed. Finally, geohazard susceptibility zoning was mapped using logistic regression and geography information system tools. The results of the susceptibility zoning model were validated using the locations that had recorded geohazards in recent decades; the accuracy of the model was greater than 86.8 %. The model validation proved that there was good agreement between the susceptibility mapping and historically recorded geohazards. The logistic regression model produced acceptable results using a receiver operating characteristics curve in which the total area under the receiver operating characteristics curve was 0.879. The results of this study can assist in preliminary planning for land use, particularly with reference to construction projects in high risk areas.