A Case Study Of The Use Of Multi-Electrode Earth Resistivity In Thinly Mantled Karst

Sinkhole formation in many areas of the northeast United States occurs in clay soils over<br>relatively shallow (<lOm), fractured, carbonate bedrock. In these areas, traditional intrusive<br>methods of site investigation have a low probability of encountering subsurface karst features<br>that are associated with future sinkhole formation. Non-intrusive methods such as ground<br>penetrating radar and electromagnetic methods have only limited applicability, and there are<br>difficulties associated with their interpretation. This paper details a case study of the use of earth<br>resistivity equipment with multiple electrodes to investigate a site in eastern Pennsylvania. Site<br>geology, selection of resistivity line orientation, data interpretation, and comparison of results<br>with intrusive borings are discussed. Recommendations for site investigations in thinly mantled<br>karst are given.