MAMMOTH CAVE NATIONAL PARK: USING ELECTRICAL RESISTIVITY AND REFRACTION MICROTREMOR TO IDENTIFY CAVE PASSAGEWAYS

Mammoth Cave National Park is a historic nature preserve located in Western Kentucky. In the park there is an unmapped section of cave from the River Styx Spring to the sumped river section underground. This section is approximately 1200 feet long. Electrical Resistivity and Refraction Microtremor surveys were conducted over the unmapped section of River Styx in order to locate and connect the conduit to other previously known and mapped caves.

The Electrical Resistivity survey included seven lines, each totaling 1200 feet in length at approximately 120 feet apart, depending on terrain. This allowed for a total depth of 400 feet, or one third of the total length of the line. Each of the seven lines used a total of 84 electrodes spaced at 15 feet apart. With the 15-foot spacing, this allowed for a resolution determined by taking half the total space between electrodes, of seven and a half feet. EarthImager 2D was then utilized to model the resistivity data collected. The Refraction Microtremor surveys were used to confirm the previous Electrical Resistivity results. Each survey length was determined based on the depth of the conduit at that point.

The data that were collected connected the River Styx Spring to the sumped section of River Styx in the cave. Electrical Resistivity was the main method used and Refraction Microtremor was used as a second means to corroborate the original data. Further research may be planned to locate other unmapped passageways on Mammoth Cave National Park.