Application of the OhmMapper resistivity-meter to detect the theatre of Sentinum Roman town by using 3D resistivity model

Th e application of geophysical methods to investigate the near-surface soil layers containing anthropic products has been recognized as an important element of archaeological research by the international community.(Clark, 1996). Geophysics can delineate quickly the presence of archaeological structures without invasive stratigraphic excavation. In particular, resistivity surveying can be used to understand the geometry and depth of the anthropic element buried in the subsoil, due to the diff erent resistivity properties between potential archaeological targets and the surrounding environment (Loke, 2004). Geoelectrical data are traditionally acquired with a galvanically- coupled resistivity system. Placing electrodes in the soil is the greatest practical diffi culty for it is time consuming and prevents rapid investigation, especially in the case of a three-dimensional survey. Th is problem can be avoided using the new OhmMapper (Geometrics Inc.) capacitive-coupled resistivity system designed to be pulled along the ground as a streamer that realizes an almost continuous profile.Th e regular urban nature of the settlement of Sentinum (Sassoferrato municipality, Ancona, Italy), typical of cities planned by the Emperor Augustus (1st century BC-1st century AD), has been confi rmed by magnetometric investigations carried out some years ago (Bottacchi and Hay, 2008). Nevertheless, one paradigm of Roman cities, the theatre, is missing from this city plan obtained by means of geophysical prospection. Th e ultimate objective of this study is to detect the theatre of Sentinum using a 3D resistivity model created by OhmMapper. www.cairn.info/revue-archeosciences-2009-1-page-267.htm