Identification of surface rock types in Durin mbelang kutambaru area Langkat, North Sumatera, using 2D resistivity imaging

Abstract

The research has been carried out to identify subsurface rock types in the Durin Mbelang area of Langkat Regency. In order to to determine the variations of rock resistivity values and subsurface structures 2D resistivity imaging technique was utilized. The 2-D resistivity imaging technique utilized Schlumberger electrode array configuration because this array is moderately sensitive to both horizontal and vertical structures. Six lines were surveyed for subsurface rock identification. The length for each survey lines is 155 m. The survey site shows the resistivity value varies about 5 - 2500 Ohm-m. The maximum depth of investigation survey is 29 meters. In general the results show that the subsurface is made up of clay and alluvium and the high resistivity values of more than 1000 ohm-m near the surface is due laterite and the end of the depth can be interpreted as mixture of weathered material or bedrock and at the depth of 28 meters is dominated by limestone.