Use of a Slope Stability Index Based Predicting Tool for Landslide Hazard Mapping in Sri Lanka

The objective of this project was to check the applicability of a deterministic model called SINMAP for landslide hazard zonation in Ratnapura area, Sri Lanka. 
The study area, Ratnapura is located in the central highlands of Sri Lanka. In this project, a deterministic model approach SINMAP was used for the evaluation of the slope stability, and the landslide hazard map output by the model was compared with that produced by the National Building Research Organization (NBRO).

      The NBRO was using a probabilistic method where the implementation of such approach is not only time consuming but also expensive. Statistics of the SINMAP output showed that 65% of the study area were stable while the remaining 35% of the area is quasi-stable and unstable. From the field records, 79% of the recorded instabilities were found to fall into quasi-stable and unstable zones. Based on the results from this study, it was expected that the use of SINMAP model to delineate the unstable regions could be extended to other areas easily where the NBRO’s method has not been implemented due to financial constrains.