Geology and terrain analysis at reserved forest Gunung Rabong, Gua Musang, Kelantan

This research focused on the geology and terrain analysis in Gunung Rabong forest, Gua Musang Kelantan. Based on the previous research, there was a lack of information on terrain analysis. Furthermore, updating the geological map is required because there are changes in the geological data. The objectives of the research area to produce the geological map of the study area in scales 1: 25000, to produce a terrain classification map and to determine the suitability zone for construction area. In order to achieve the objective, Geographic Information Systems (GIS) is used to produce the result and making interpretation based on cut and fill slope, fill slope, terrain analysis, slope gradient, terrain morphology, activity of slope, erosion and instability and cover & vegetation. The lithology of the study area was granite, interbedded shale, sandstone and quartzite and they included in the Permian to Triassic age. For terrain analysis study, construction suitability map were produced based on terrain classification. In the study area, there were four type of class, which as class I (30.54%), class II (33.9%), class III (27%) and class IV (8.6%). The classes were determined by analyze the slope gradient, terrain code, activity code and erosion & instability. The study area was dominated by class I and class II and the constructions in Class II areas require cutting, filling, and erosion are expected on bared slope when surface runoff is not properly channeled. Construction in these areas was not expected to encounter any major foundation problems. Bedrock may encounter during excavation. From the slope terrain analysis, the site is mainly moderate steep slopes (15° - 25°) to steep slopes (25° - 35°) which cover 26.74% and 45.53% respectively. Flat to gentle slope (0° - 15°) covers 18.9% of the study area. Only 8.6% of the site is covered by very steep slope (>35°).