Results of geophysical scanning of a Roman senatorial villa in the Santa Marina Bay (Croatia, Istria) using the amplitude data comparison method (ADCM)

The article presents application of the new geophysical amplitude data comparison method (ADCM), resulting from integrated geophysical survey using ground-penetrating radar (GPR) and magnetometry. The ADCM was applied to recognize the horizontal and vertical stratigraphy of a Roman senatorial villa located in Santa Marina (western part of Croatian Istria). The measurements were carried out in 2017−2019 at this site, accompanied by a use of GPR and gradientometer. These two methods significantly differ from each other, but on the other hand, they are complementary to some extent. This is due to the fact that the methods register different types of underground materials. The GPR records electromagnetic waves reflected from real buried remains or boundaries between geological or archaeological layers that differ significantly in electrical properties. The magnetic method, in turn, records the anomalies of the magnetic field intensity resulting from the underground concentration of ferromagnetic minerals, hence it is ideal for searching structures filled with organic matter or burning material. However, a separate usage of these methods does not guarantee a full picture of archaeological structures that are preserved underground. Only the application of the ADCM allowed for a comparison of GPR and magnetic amplitude data reading, following which a spatial image (2D and 3D) of the preserved archaeological structures and the geological stratigraphy of the Santa Maria site were obtained.