Low-Frequency Ground Penetrating Radar: A Versatile Tool for Multiscale Analysis in Active Tectonics, Geoarchaeology, and Urban Geology

In situ geophysical techniques are essential tools in geological and geotechnical research for characterizing tectono-stratigraphic settings. Since its introduction in the late 1970s, Ground Penetrating Radar (GPR) provides integrated information over a large subsoil volume, overcoming the limitations of conventional point-scale direct survey or measurements. In the last decade, advances in low-frequency GPR systems have made them efficient and affordable for multiscale investigations. Compact and lightweight monostatic antennas, such as the COBRA Plug-In SE 70 employed in this study, allow for rapid deployment, flexible parameter settings, and high-resolution data acquisition. Operating with a center frequency of 80 MHz, a frequency range of 20–140 MHz, and a maximum penetration depth of 50 meters, this system achieves vertical resolutions of approximately 30 cm with a sampling rate of 32,000 sample/s. This study presents the results of low-frequency GPR surveys conducted in different geological contexts in Southern Italy:1) active tectonics at Mt. Camposauro (Southern Apennine, Italy) an area of energetic historical seismicity with evidences of recent tectonic activity; 2) geoarchaeology and site characterization of subsurface caves at the ancient Capua, an Etruscan city (IX century BCE) lately conquered by  Osci, then by Samnite (IV century BCE) and finally by Romans, becoming in the III century BCE the main city along the Via Appia, regina viarum;  and 3) urban geology in Calitri Town (Avellino, Italy) an area with a complex tectono-stratigraphic setting, affected by seismically induced gravity-driven deformations. The results highlight the versatility and effectiveness of low-frequency GPR for investigating geological processes at varying spatial and temporal scales. Key findings are summarized and discussed, emphasizing the role of GPR as a preferred method for integrated subsurface analysis.