Landslide Susceptibility Map Preparation Using Multiple Regression Method (Case Study: Ilam Dam basin)

In recent years, landslides occurrence has been increased in different regions of Iranbecause of different agents, especially road construction. Therefore, inspection of thisphenomenon including effective agents in landslide occurrence, determination ofsusceptible area … is necessary to prevent the landslides formation. For this purpose,the Ilam dam basin having 476 (km2) area was selected for investigations. At thebeginning of this research, after field investigations, seven factors including: geology,slope, aspect, fault, drainage network and land use were recognized as primary effectiveparameters in landslide occurrence. In the next stage, the information layers of aboveparameters were prepared in Geographic Information System (GIS) environment usingArc view 3.2 software and these maps were overlaid with the landslide inventory map.Analysis of the results indicated that aspect factor has minimum effect on landslideoccurrence in the area. Then, using the six remainder factors, homogeneous units map isprepared. In order to quantify the factors and give an appropriate weight to theparameters, the slide area percentage in each unit was calculated. Multiple regressionswere used for statistical analysis. The distance from faults and land use parameters wereput aside by the model. The results showed that the four factors including road, slop,drainage network and geology have the highest affect on landslide occurrencerespectively.