Landslide Susceptibility Mapping In Huachi Country Of Gansu Province, China

Landslides amongst the most destructive geological disasters, cause many scientists interests in research and some of them have already devoted to landslide susceptibility mapping. Landslides always occurred in mountain areas, have a clear physical relationship with the lines of valley and ridge so that slope units seem to work as effective mapping units for landslide susceptibility mapping. But slope units are deficient to depict surface with flat component. The existing method to dividing slope units only adds flat component into slope unit, thus calculated factors would have a big gap from the actual. Plus, this method breaks the formation law of regional water and irrationally extracts subwatersheds in reversal DEM. This paper proposes a new method of dividing mapping unit. Also information on the application process and the performance of this unit would be further manifested by giving an example from Huachi.?The terrain breaks could be obtained by watershed segmentation of the mean curvature and the reversed and merged for mapping unit division. Mapping units on inclined surface turn out to be divided by ridge lines, valley lines, tableland rims and basin rims, are considered as generally slope units. Accordding to statistics of morphological parameters flat unit has a more uniform size, an overall shape between circular and equilateral triangle and a few variation of inside terrain.?Totally 12 environmental factors involving elevation, lithology and road distance are selected and counted for each unit in order to obtain its assessment factors. Using frequency ratio method and MCDA model as the evaluation model, landslide susceptibility mapping was finished. The area under the landslide success rate curve basically above 0.9, the proposed mapping unit is reasonable to apply in landslide susceptibility mapping.