General geology and determination of potential limestone geohazard by using Electrical Resistivity Imaging (ERI) at Batu Neng and Batu Machang, Gua Musang, Kelantan.

Gua Musang town is well known due to it magnificent beauty of limestone karst hill. This Permian age limestone shows the various features such as stalactite and stalagmite, cavern and pinnacles. Therefore, there were probably the present of karstic features on the subsurface limestone bedrock. Since the location of the limestone hill is near to residential area, there was an important factor for this study about the potential limestone geohazard which would bring harm, lost or might be a catastrophic event failure. The objectives of this study is to update the geological map of study area with scale 1:25000 and to determine the potential limestone geohazard, sinkhole by using geophysical method, Electrical Resistivity Imaging (ERI) at Batu Neng and Batu Machang, Gua Musang, Kelantan. This study area is within 5km² area with latitude ranging from N 04° 49’ 4.863” to N 04° 51’ 48.63” and longitude ranging from E 101° 57’ 8.105” to 101° 59’ 50.251” while for resistivity survey is focusing on two limestone hills, Batu Neng and Batu Machang. Geological mapping has been conducted to collect the surface geological information of the study area while the resistivity survey is to determine the potential anomaly by referring to the resistivity values of subsurface material at the study area. This resistivity survey was carried out using Lung Imaging system which consisted of ABEM SAS4000 Terrameter, electrode selector ES464, 2 unit of 100meter cables, 41 steel electrodes with wire clipper. The electrode configuration for this study is pole-dipole and dipole-dipole with 200 metre length and 5 metre electrode spacing. The measured resistivity value was processed using selected inversion software, RESZDINV to obtain the 2-D resistivity profile of surveyed line. The result shows the present of potential cavity in all survey line in future