2-D Electrical Resistivity Tomograph & Induced Polarisation Survey on Detection of Karst Features

The presence of naturally formed voids/cavities and solutioning channels in the subsurface karstic limestones can cause severe problems in civil/geotechnical engineering and mining projects. Peninsular Malaysia has various types of karstic limestone, sinkholes, solutioning cavities and channels. To effectively appraise the karstic formation, electrical resistivity and induced polarisation techniques have been proven a cost-effective solution for investigating subsurface bedrock profile, solution channels and its connectivity. A case study using 2-D electrical resistivity tomography and induced polarisation survey for a limestone quarry site is used to illustrate the successful application in identify the location of the karst features. Data processing has been carried out taking into consideration of the collective response of resistivity and induced polarization (IP)/chargeability that helps in interpreting subsurface strata, seepage path in the upper alluvial deposits, location of porous/jointed limestone rock mass or/and karst features with potential seepage flow, and the infilling condition of the joints and voids.