Integrated Seismic Refraction and GPR Survey for Subsurface Characterization at an Ecological Research Site

Abstract. This study presents an integrated geophysical approach for shallow subsurface characterization using seismic refraction and Ground Penetrating Radar (GPR) at the Florida Atlantic University Boca Preserve. A 240 m transect was surveyed using 48 geophones and three GPR antenna frequencies (80, 160, and 450 MHz) to capture complementary acoustic and electromagnetic responses. Seismic data were processed through first-arrival picking and layered inversion, while GPR data underwent time-zero correction, filtering, background removal, and migration. The integrated interpretation, supported by nearby borehole information, delineated four principal subsurface units: loamy soil (0–3 m), dry sand (3–8 m), saturated sand (8–30 m), and a probable limestone layer below ~30 m. Both methods independently identified a strong boundary near 7–8 m corresponding to the water table, demonstrating excellent cross-validation between seismic velocities and dielectric contrasts. The results highlight the effectiveness of combining seismic and GPR techniques for non-invasive characterization of heterogeneous coastal environments. The derived stratigraphic model provides a useful foundation for ecological restoration planning, groundwater assessment, and future geophysical studies within the preserve.