Three-dimensional electrical resistivity for detection of subsurface karst associated with Friesenhahn Cave

摘要

Electrical resistivity imaging techniques have proven to be an effective technological advancement for detecting subsurface karst features in carbonate formations. Numerous variables, such as electrode configurations, moisture conditions, carbonate lithology, and structure, can affect how effectively and accurately the generated images replicateactual underground features. This study investigates the electrical resistivity of Friesenhahn Cave and the surroundingstrata and attempts to predict the morphology of what are believed to be extensions to the currently known singlechamber of Friesenhahn Cave. Current observations within the known cave clearly show a collapsed entrance, whichhas been dated to the Pleistocene. Observations of water flow, as well as the collapse of sediments from sections ofthe cave floor, indicate a potentially significantly-sized additional passage extending beyond the known cave. Electricalresistivity results also provide an opportunity to determine the point of easiest access to the extension chambers soas to minimize the excavation efforts needed to obtain physical access to them from the existing cave. Assuming access to those chambers, physical measurements of the extension chambers will be used to confirm the results of thedipole-dipole array.