On the capability of very high resolution satellite and ground probing radar techniques for detecting buried archaeological adobe structures

Adobe (sun-dried earth material) is a common prehistoric building material that had been widely used for several thousand years mainly in arid and semi-arid lands where generally other building materials are quite scarce. In particular, the earthen construction materials have a long history in Southern America and in the Andean prehistory of the Peruvian coast, where the hyper-arid climate has promoted an excellent preservation of archaeological adobe remains. The detection of buried earthen structures is particularly complex to perform due to the subtle contrast between the archaeological features and the surrounding areas. The use of Earth Observation (EO) to detect and document buried archaeological adobe structures can open new perspective but up to now it presents one of the major challenges to archaeological investigation. In this paper we present our preliminary results obtained from the assessment of the potentiality of satellite Very High Resolution (VHR) optical imagery and Ground Penetrating Radar (GPR) in detecting adobe archaeological setting. Satellite VHR imagery and GPR have been used for three significant test sites selected inside the Cahuachi Ceremonial Centre of the Nasca culture (Southern Peru) one of the most important archaeological area of ancient Peru. It is a remarkable example of adobe architecture in Southern America. The spatial extension of the archaeological site has been estimated as large as 25 square km, and this makes the Ceremonial Centre of Cahuachi the biggest in the world and gives a clear idea of the importance of the Nasca civilization. Results obtained from our experimental analysis pointed out the high potentiality of both satellite VHR and GPR when applied to detect, investigate, and document earthen archaeological remains.