INTEGRATION OF TWO GEOPHYSICAL TECHNIQUES TO INVESTIGATE A BURIED FOUNDATION: A CASE STUDY OF GUSTAVUS ADOLPHUS, SUSQUEHANNA UNIVERSITY

An investigation to determine the effectiveness and accuracy of geophysical techniques such as Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT) together to explore buried foundations. This study was conducted on the former site of Gustavus Adolphus (GA) Hall at Susquehanna University, in Selinsgrove PA. GA was constructed in 1895 and burned down in 1964. GA’s location was used as an experimental site. Multiple surveys were performed onsite including a large GPR survey, with a 32x37 m2 grid where the survey lines were spaced by 50 cm, was conducted to ascertain the locations of any remaining buried foundations of the site. Two small GPR surveys, one with 400MHZ and the second with 900 MHZ, in addition to an ERT survey all performed on the same 7x14 m2 grid area, were then implemented to further visualize the area of the foundation that was depicted in the large survey grid. The study also focused on comparing these geophysical techniques with one another or the combination of them. Using both 2D and 3D models a section of GA structure was made visible. The model shows a long wall extending east-west in addition to a large anomaly south of the building which is believed to represent the stairs of GA. This anomaly was also shown on the ERT model as a high resistivity area.