Seismic reflection profileNB-1. Seismic profiling uses sound waves to determine subsurface geology, much like an X-ray uses radiation to "see" inside the human body. Sound waves bounce off the boundaries between different rock types to produce reflections. The NB-1 seismic profile is located to the southwest of the New Jersey – Pennsylvania border (see map in a). In b is an uninterpreted version of the seismic profile. In c is the interpretation of the profile, constrained by reflection geometry, surface data, and well data. Modified from Withjack et al. (2013).