Prospections non invasives sur le site de Mustis/Musti (El Krib) en Tunisie

Abstract

The objective of the first step of the non-invasive survey carried out on the Mustis site described herein was to verify the possibility of locating archaeological remains and to detect the location of the supposed remains by geophysical measurements (magnetic and electric methods). Magnetic measurements were made with Geometrics G-858 Cesium magnetometer with two probes located on the same horizontal level at 0.5 m distance or on the same vertical level at 0.5 m and 0.75 m above the ground level. The instrument recorded the values of the total vector of the magnetic field strength and made it possible to calculate the pseudo-gradient of its components (horizontal or vertical). Electric measurements were made by means of axial dipole-dipole electrode configurations (parallel) with AB current electrodes with spacing of one metre and electrodes of potential MN (identical spacing) at equal distance D at 4 and 6 metres, which made it possible to record values of apparent resistivity of the subsoil, with the penetration depth of the current of c. 2.0 and 3.5 m, respectively, below the current ground level. At the time of the data interpretation, the suspected locations of the remains causing the anomalies were indicated by means of dashes of different colours and thicknesses (depending on the assumed depth of the structures). These indications, transferred on maps, can serve as a starting point for extensive analyses of the entire site and its surrounding area. The first non-invasive surveys carried out in Mustis have demonstrated the usefulness of magnetic and electric methods in mapping the preserved remains both inside and around the city. The obtained results enabled elaborating a strategy for the work to come. It is quite probable that the magnetic method will prove capable of indicating places where vestiges of constructions are preserved, while the electric method will determine the depth and conditions of deposition of localised structures.