GIS based landslide hazard evaluation and zonation - A case from Jeldu District, Central Ethiopia

In the present study landslide hazard evaluation and zonation (LHZ) was carried out in Jeldu District in Central Ethiopia, about 156 km West of Addis Ababa, the capital city of Ethiopia. Through field based inventory mapping and image interpretation 34 past landslides were mapped in the study area. The governing factors; aspect, slope and elevation, were determined from the digital elevation model (DEM), which was obtained from the ASTER satellite. Lithology was adopted from the geological map of Ethiopia (1:2,000,000), while the soil and land use/land cover were processed from Landsat + ETM satellite data. All governing factors were statistically analyzed to find the correlation with the past landslides. In this study, statistical - probabilistic approach was used to rate the governing factors and then customized raster calculation was made in GIS environment to develop the LHZ map.The results revealed that 12% (5.64 km2) of the study area falls under no hazard, 27% (12.69 km2) as low hazard, 32% (15.04 km2) as moderate hazard, 21% (9.87 km2) as high hazard and the rest 8% (3.76 km2) as very high hazard. The validation of LHZ map shows that, 92% of past landslides fall in high or very high hazard zones, while 6% fall in medium and only 2% in low landslide hazard zones. The validation of LHZ map thus, reasonably showed that the adopted methodology produced satisfactory results and the delineated hazard zones may practically be applied for the regional planning and development of infrastructures in the area.