Geology and rockfall potential assessment using GIS at Gua Musang, Kelantan

This research was conducted at two study areas within the Gua Musang, Kelantan. The study areas were overlaid to one another about 25%. The aims of the study are to update the geological map of the study area, to evaluate the parameters of rockfall at karst area, and to produce rockfall potential zone map for limestone karsts at Gua Musang town area. Geological mapping was focused at the first study area that expends up to 25km2from Kampung Kundur at latitude 4°56'34.00"N to 4°53'51.91"N and longitude 101°59'45.76"E to 101°57'4.02"E. An updated geological map of Kampung Kundur with the scale of 1:25,000 was produced. Permian – Tertiary rock units comprised of metasedimentary, limestone, rhyolite, and granite were discovered in this study area. Besides, rockfall potential assessment was carried out within the second study area that expends up to 26km2around the Gua Musang town at the latitude 4°53'49.22"N to 4°51'05.13"N and longitude 101°54'58.60"E to 101°57'41.26"E. Nine selected limestone karsts, including Gua Musang, Gua Serai, Gua Batu Boh, Batu Neng, Batu Machang, Batu Papan, Gua Madu and two karsts at KESEDAR Etnobotany Park were observed during the drone mapping. Buffer analysis is the tool in Geographic Information System (GIS) that was used in generating the rockfall potential zone map for this karstic area. Five rockfall parameters, including rainfall intensity, slope density, height, vegetation density, and discontinuities and karst features were weighted, and overlaid to determine the rockfall potential for each slope zone at the limestone karsts. The resulting rockfall potential map classified three zones of rockfall potential, from high potential zone (16%), medium potential zone (71%), and low potential zone (13%).