Georadar survey inside the Santa Maria Maggiore church of Ispica (Sicily-Italy)

The results of a ground penetrating radar (GPR) survey, inside the Church of Santa Maria Maggiore of Ispica (Ragusa), Sicily, are reported to highlight the presence of anomalies likely due to the existence of crypts and/or cavities beneath the church floor and the adjacent sacristy. The data have been acquired along sections by adopting a multi-array configuration with acquisition frequencies of 250 and 500 MHz. Calibration of the electromagnetic instrumentation was done using the information obtained from a stratigraphic section by mechanical drilling, undertaken near the investigated area and that reached a depth of 40 m from the surface revealing the presence of a calcarenite bench, affected by sub-vertical fractures. From the interpretation of the profiles, the presence of shallow electromagnetic anomalies has come to light in the areas of the naves and the sacristy, probably associated to the existence of cavities and/or crypts, empty or partially filled by rubble, which accords well with the archeological history of the site.