Alternative Title

NCKRI Symposium 2: Proceedings of the Thirteenth Multidisciplinary Conference on Sinkholes and the Engineering and Environmental Impacts of Karst



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Publication Date

May 2013


pg(s) 213-219 Electrical resistivity tomography (ERT, also called ERI) is commonly used to identify geologic features associated with sinkhole formation. In covered karst terrain, however, it can be difficult to resolve the depth to top of limestone with this method. This is due to the fact that the sediments mantling the limestone are often clay-rich and highly conductive. The resistivity method has limited sensitivity to resistive zones beneath conductive zones. This sensitivity can be improved significantly with electrodes implanted at depths near the top of limestone, in addition to readings at the surface. Deep electrodes are installed with direct push technology, placing an ERT array in the clay-rich karst cover near the top limestone surface contact. This method, which we are calling Multi-Electrode Resistivity Implant Technique (MERIT), offers the promise of significantly improved resolution of epikarst and cover collapse development zones at the limestone surface sediment interface in heterogeneous karst environments. The technique could also help reduce the effects of cultural features typically encountered by surface electrical resistivity surveys in urban environment. The results of a case study sinkhole investigation in west-central Florida show the applicability of MERIT. At this site the resistivity array length is restricted to 60 meters. The depth to the top of the limestone lies at ~15 meters. Electrodes were implanted both at the surface and at 10 meters depth every 3.3 meters along a profile 50 meters long. The combination of both surface and deep measurements improves the resolution of the sediment-limestone interface over that from surface measurements alone. Open Access - Permission by Publisher See Extended description for more information.


Conference Proceeding


University of South Florida





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