IDENTIFYING SINKHOLES USING INFRARED AERIAL IMAGERY

As part of an undergraduate research project, the author utilized thermal and near infrared cameras, both handheld and Unmanned Aerial Vehicle (UAV)-mounted, along with 3D photogrammetry, to investigate karst processes at the Selu Nature Conservancy owned by Radford University. This research builds on investigations conducted over 15 years ago. At that time, sinkholes were mapped using standard survey techniques and no entrances to large underground voids were identified. More recently, holes connecting to underground voids have opened in at least two sinkholes.

With that in mind, the author used UAVs, carrying standard and infrared cameras, as well as handheld infrared cameras and a Garmin GPS system, to examine and map sinkholes in the study area. Those were then compared to existing maps. Recent studies have shown that both aerial and handheld infrared cameras recorded average temperature differences between the openings and the surrounding ground for each location of about 12 degrees Celsius during the spring semester. This has been consistent among openings that have been observed and investigated in the area.

This is a continuation of recent studies performed by the author and expands them to include the use of near infrared imagery in an effort to evaluate whether plant life is impacted by the formation or expansion of cave openings. The author will also describe UAV flights incorporating thermal infrared imagery to ascertain if the findings of the author’s previous work remains true during other times of the year.