Part of Mundell & Associates’ Geophysical Team Forrest Kunkel and Eric Chojnowski and interns Amanda and Marita were featured on the front page of The Herald Times of Bloomington this Monday for their work on subsurface imaging of the grounds of the Monroe County Courthouse using Ground Penetrating Radar (GPR).
GPR is an electromagnetic technique which detects interfaces between materials with different electrical conduction properties or dielectric permittivity. GPR is non invasive, meaning it allows for detailed characterization of study areas without the need to drill or disturb the surface.
This method works by sending a pulse of radar energy into the ground and recording the strength of the return signal and the time it takes to return. When the energy passes through materials of different properties, it sends signals of different strengths. After surveying a site, a cross section of the reflections is viewed and analyzed.
GPR can be used for many applications to locate discrete objects and/or geological features. In the case of the Monroe County Courthouse, the city of Bloomington is hoping to find the exact locations of the first county library and a city fire station which were torn down in the early 1900s. Additionally, the discovery of a public outhouse (which is believed to be on site), could lead to some interesting archaeological finds.
The county plans to release information to the public about Mundell’s report, include data in their Geograhpic Information System website, and use the knowledge to maintain any historical treasures found underground. Stay tuned!