Mapping of Landslide Hazard Zones in Jordan Using Remote Sensing and Gis

Preliminary studies are required before the construction of a highway in order to meet certain objectives, such as low cost, accessibility to urban facilities, compatibility with land use, efficient use of resources, and stability of hill slopes. For stability of hill slopes, a landslide hazard zonation map should be prepared so as to select proper road alignment, in order to provide quantitative measures to be taken by the designer in unstable, hazard-prone areas. Preparation of such a map involves handling a huge amount of data, and it can be done in either of two ways: manually or using computer software such as a geographic information system (GIS). A GIS technique is employed in this study to integrate the instability factors. The intersection of these factors using this technique enables users to classify an area into zones of varying degrees of instability. An area of approximately 1,300 sq km divided into 1,603,000 pixels along the Amman-Irbid highway was chosen for this study. Between 1966 and 1971, four major mass movements took place, and in 1991/1992 seven more major landslides occurred along the same highway at a time when it was under reconstruction and expansion. The main objective of this paper is to report on the integration of spatial data for the purpose of establishing a mass movement hazard zoning map using a GIS. To fulfill this objective, a structural model was developed. It was built in two consecutive stages. The first stage consists of transformation of data collected and a first-step integration of spatial data to delineate the major causative factor maps. In the second stage, a stepwise sequence of integration was performed to combine all the maps obtained in the first stage. The results obtained from the landslide hazard zoning map agree well with the landslides observed in the field.