MAPPING OF MASS MOVMENTS SUSCEPTIBILITY BY USING SATELLITE IMAGE AND GIS TECHNOLOGY

Landslide susceptibility assessment, effected by means of geostatistical methods, is based on the analysis of the relationships between landslides and the spatial distributions of some instability factors. In this study, a detailed landslide susceptibility map was produced using a data driven objective bivariate analysis method (weights of evidence, WOE) with datasets developed for a geographic information system (GIS). We applied this methodology for the first time to Moroccan region. Known as one of the most landslide prone area in the Rifain Morocco, the Zoumi sector was selected as a suitable case because of the frequency and distribution of landslides. The site covered an area of 613 km2 with a landslide area of 81 km2. Several data domains were used, including, multitemporel remote sensing data and products, topographical maps, geological maps, and thematic maps, all with 30 X 30m pixels. Using landslide and landslide causative factors we developed a statistical relationships for landslide susceptibility. All continuous variables were converted to categorical variables according to the percentile divisions of seed cells, and the corresponding class weight values were calculated and summed allowing the Zoumi susceptibility map creation. According to the obtained susceptibility map 22,91% of the study area was identified as high susceptibility. Moderate susceptibility, low and null susceptibility zones covered 41,04 %, 13,32 %, and 22,73 % of the area, respectively. The high and moderate hazardous zones are along overlapping faces of the study area, being in agreement with the actual distribution of landslides.