ABSTRACT
ABSTRACT: It is now widely acknowledged that archaeological sites are almost everywhere increasingly threatened by many natural and anthropic agents. Dealing with essentially nonrenewable cultural resources, archaeologists are as a consequence becoming more and more concerned about their husbanding. Many signifi cant data can be obtained by applying remote sensing, visual and infrared aerial sensing, surface surveying and the more limited methods of pedestrian surveying, surface collecting and shovel testing. With specifi c symbols this kind of information can be reported on topographic maps. Their combination can provide some close correspondence between the remote sensing indications and the presence of sites frequented by men. The preliminary analysis of materials could also provide a dating, but it is generally not possible to establish extension and depth of any archaeological settlement. Only applying geophysical prospecting methods this further information can be properly achieved. Nowadays, non-destructive ground surface geophysical prospecting methods are increasingly used for the investigation of archaeological sites, which implies detailed physical and geometrical reconstructions of hidden ambients. The probability of a successful application rapidly increases if a consistent multimethodological approach is adopted, according to a logic of objective complementarity of information and of global convergence toward a high quality multi-parametric imaging of the buried structures. Non-invasive geophysical prospecting methods are to-date the only means available for local reconnaissance and discrimination, prior to any excavation work. Geophysical methods can measure various physical properties of the subsurface soils and rocks. Such properties are not only shaped by geophysical processes but they can also refl ect alterations caused by humans. Many methods were originally designed to measure geophysical features at the scale of several metres or kilometres, while archaeological features are of interest at the scale of centimetres or a few metres, at most. Thus, some methods can be readily adapted to archaeological sites, while others are of marginal or negligible value. Traditionally, the geophysical methods are classifi ed into the two main groups of passive and active methods. Within the fi rst group, the amplitude of nearly steady gravitational, magnetic and electrical perturbation fi elds, generated by buried features, are measured at the sensing device. In the second group, artifi cial electrical, electromagnetic and acoustic signals are emitted by the device, which then senses the return signals, more or less altered by the typical responses of the subsurface features.
