Author:

Keywords:

landslide hazard map, lithology, remote sensing, data integration, Science & Technology, Technology, Remote Sensing, Imaging Science & Photographic Technology, ZONATION

Abstract:

Landslides are the result of processes, which include geological, geomorphological and meteorological factors. The most important factors are lithology, structure, drainage, slope, land-cover, and geomorphology. In order to make a landslide hazard map, all these factors need to be analysed in order to define the instability in a region. Remotely sensed data provide valuable information for determining the occurrence of landslides, such as recent land-cover and fractured zones. • The method of landslide hazard analysis, which is applied in the Thua-Thien-Hue Province (TTH), is based on the methodology of Chung and Shaw (2000) with the following assumptions: Future landslides will occur under circumstances similar to the ones of past landslides in either the study area or in areas in which experts have obtained their knowledge on the relationships between the causal factors and the occurrences of the landslides. • Spatial GIS data representing the causal factors can be used to formulate the future landslide hazard. Data integration was carried out using the ordinal scale (qualitative) relative weighting rating technique to give a Landslide Hazard Index (LHI) value. The breaks in the LHI frequency diagram were used to delineate various landslide hazard zones, namely, very low, low, moderate, high and very high. Field data on landslides were employed to evaluate and validate landslide hazard zonation map (Saha, 2002). This paper describes the methodology used and the generation of seven thematic layers: 1) recent land cover; 2) geological fracture zone map; 3) weathering rock map; 4) geotechnical map; 5) geomorphological map; 6) slope map and 7) DEM. It is shown that the potential landslide hazard map can be established by statistical correlation of landslide frequency with these seven factors. The applicability of the map is shown by the fact that the Vietnamese government and NGO-projects take account of the results for their development planning in TTH.