GEOPHYSICAL INVESTIGATION OF THE BROAD TOP COALFIELD AREA, SOUTHERN PENNSYLVANIA

A geophysical investigation utilizing reflection seismic, electrical resistivity, and induced polarization methods was conducted over a 75 mi² area in the vicinity of the Broad Top Coalfield in Bedford, Fulton, and Huntingdon Counties in South-Central Pennsylvania. The primary goal of this project was to evaluate the ability of these geophysical methods to detect and resolve geologic structures, formation contacts, fault and fracture zones, and related features in the area of interest.

Project results support the use of reflection seismic and electrical resistivity geophysical methods in local and regional geological field mapping efforts. Paleozoic bedrock in the site area was identified and mapped from the ground surface to Pre-Cambrian basement (greater than 30,000 feet below ground surface) using a combination of mapped surface geology, reflection seismic and electrical resistivity geophysics. Electrical resistivity methods are useful from the ground surface to depths of approximately 1,000 feet in identifying fault and fracture zones, lithologic variability across stratigraphic boundaries, and variations in fluid saturation. Previously collected vibroseis data from the 1970’s and newly collected reflection seismic data are shown to be useful for interpreting structures, stratigraphy, faulting, and reconstructing complex geologic histories in the Broad Top area.

It is likely that these tools would be useful for many geological mapping purposes throughout significant portions of Pennsylvania and the Appalachian Basin.