EXAMINING HUMAN IMPACT INSIDE A SHOW CAVE BY MAPPING THE SPATIOTEMPORAL DISTRIBUTION OF HISTORICAL SIGNATURES AT GRAND CAVERNS, GROTTOES, VA

Geotourism in caves, as a form to build wealth, goes back to the 17^th century in central Europe. In the U.S., Grand Caverns (GC), located in the town of Grottoes, VA, started operations back in 1806, making this location the oldest and continuous show cave in the country. Original tours at GC encouraged visitors to “leave a mark for posterity” by signing the walls of the caves and several speleothem formations with their names and date of the visit. Even if this practice started to be prohibited by 1973 with the resurgence of the Virginia Cave Protection Act (1966). On this ongoing project, we are collecting four-digit (year) dates at a resolution of 2m using the current tour trail walls and speleothems and form the ground up to 2m to sample 400 m of trail. As way to understand spatiotemporal distribution of the signature, collected signatures are going to be plotted on a high-definition point cloud of 271.2 x 10⁶ points of GC, constructed with mobile lidar with SLAM (simultaneous localization and mapping) technology. Preliminary results shows that 88% of signatures occur starting at 80 meters within the cave with dates ranging from 1864-1962 with an average distance from the ground of 145.4 cm. Additional data to be included in this study is radiocarbon dating of pre-treated wood, as well of other objects found in nearby off trail locations. This study has the objective to provide an alternative method to portrait human impact in historical locations, as well data to support current conservation efforts of caves at GC and other show caves in the Shenandoah Valley.