Case Histories of GPR for Animal Burrows Mapping and Geometry

Ground Penetrating Radar (GPR) has a wide range of applications, from geologic mapping to concrete inspection. A recently emerging GPR application is deployment in biological investigations as a non-invasive technique. Geophysical mapping of features such as tree roots and turtle burrows has proved valuable for the understanding of these subsurface systems for ecological, environmental, or engineering purposes. Four case histories of GPR investigations pertaining to animal burrows are described: cutter ants in Brazil, groundhogs in Michigan, and groundhogs and burrowing bees in Pennsylvania. Cutter ants (Atta spp.) in Amazonian Brazil are known to construct burrows of nearly the same dimensions as groundhogs as they excavate galleries up to 7 m deep for leaf storage. Cutter ant burrows are hazardous to heavy equipment and may also cause loss of mud circulation during rotary drilling. Groundhogs (Marmota monax), found throughout the United States, cause unseen hazards, particularly for equestrian facilities where a sudden collapse can cause severe injuries to both horse and rider. Burrowing bees (Colletes inaequalis) are common in the northeastern United States. The size of the bee burrows is significantly smaller than that of the cutter ants and the groundhogs. The data for these surveys were collected over a twenty-year span, crossing several generations of survey equipment and processing techniques. Together, these four case histories highlight the historic and current capabilities of GPR systems applied to mapping subsurface burrow systems. These examples demonstrate the important impact near surface heterogeneities have in altering ecological, environmental, or engineering systems and the utility of GPR or mapping such heterogeneities.

Impact/Purpose

Ground penetrating radar (GPR) has been used for a wide variety of geological applications over the last several decades. This geophysical method has been successfully applied in mapping landslides (Sherrod et al. 2014; Sass et al. 2008; Barnhardt, 2000), deciphering glacial history (Blewett et al. 2014; Choi et al. 2014), concrete inspection (Baryshnikov et al. 2014; Varela-Ortiz et al. 2013; Zanzi and Arosio, 2013), and identifying zones of contamination (Cassidy, 2007; Porsani et al. 2004; Sauck et al. 1998), among many other applications. Additionally, the versatility of GPR techniques is transferable to archaeological exploration because of the ability to detect slight changes in the subsurface electrical properties making the method ideal for locating artifacts, foundations, and previous excavations. Archaeological investigations around the world have benefited from GPR analysis (Gaff et al. 2013; Porsani et al. 2010; Sarris et al. 2007; Conyers and Goodman, 1997). However, often GPR results are inherently ambiguous. For example, field sites can have multiple subsurface sources of GPR reflections that are not the intended survey target. Animal burrows and tree roots, for example, are frequently a source of noise within GPR profiles at archaeological sites (Gaff et al. 2013; Porsani et al. 2010; Sensors & Software Inc., 2010; Rodrigues, 2009).

Citation

Sherrod, L., W. Sauck, E. Simpson, D Werkema, AND J. Swiontek. Case Histories of GPR for Animal Burrows Mapping and Geometry. Environmental and Engineering Geophysical Society, Denver, CO, 24(1):1-17, (2019).

• https://www.researchgate.net/publication/333035253_Case_Histories_of_GPR_for_Animal_Burrows_Mapping_and_Geometry