Pemetaan zon tanah runtuh kawasan Bukit Antarabangsa menggunakan ARCGIS 9.3 dan model stability index mapping

Abstract

The geohazard stability assessment is very important for the prediction and management of natural disaster such as landslide, flood, earthquake and so on. For example, the analysis of landslide requires evaluation of the relationship between various terrain conditions and landslide occurrences. The aims of this study are to produce and to analyze a landslide susceptibility map for hillsite areas at Bukit Antarabangsa, Ulu Klang, Selangor. The relationship between landslide distributions and layer parameters such as slope gradient, rainfall, drainage, geology and land use have been prepared, recorded and processed in Geographical Information System (GIS) database environment. Next, the numerical weights for all factors were determined using weighted overlay method. The ArcGIS Ver 9.3 software was used to execute, manage, display and analyse spatial data for production of landslide susceptibility map at scale of 1:8 000. Weighting and ranking of causative factors to landslide occurrence have been used to predict landslide potential areas. In this study, the landslide susceptibility map was divided into four zones of stability index values: Low (0-1), Moderate (2-3), Moderate High (4-5) and High (6-8). The ranges of classification were derived from the histogram of assessment of landslide stability. Many locations of landslide occurrence are located in the moderate high and high index. The results of the soil stability map of an area of approximately 1 km2 showed that only 0.8% of the study area lies in the highest landslide prone area. Similarly, 23.4%, 70% and 5.8% of the area lies in the moderate high, moderate and low landslide prone area respectively. This susceptibility map is compared with the landslide map derived from Stability Index Mapping (SINMAP) model. In general, this study found that Bukit Antarabangsa area posed a relatively high percentage of landslides occurrence with slope angle larger than 20 degrees. Daily rainfall more than 50mm becomes a triggering factor to a landslide event at Bukit Antarabangsa and the area nearby.