Geomagnetic is a cost-effective and quick method to locate archaeological objects or structures in the underground. The magnetic properties of these objects differ from the environment’s properties producing visible magnetic anomalies. The objects can consist of pipes and tanks made of metal or archaeological structures such as waste pits, trenches, grave sites, iron objects, foundations and walls.
In the course of planned wind turbines a geomagnetic prospecting was carried out to detect archaeological objects and structures from the Roman period in the underground. The result shows positive anomaly values (black) representing Roman grave gardens which were proven by excavations.
Magnetogram with identified Roman grave gardens
Stones and remains of foundations and walls in the underground show higher electrical resistance compared to the surrounding soil. Therefore, geoelectric is a suitable cost-effective method to investigate large areas in order to localize structures like Roman estates, paved paths or medieval buildings.
Resistivity mapping was applied to explore buildings of a Roman Villa Rustica. The map shows higher resistance (red) indicating existing walls and probably floors equipped with stone slabs in the upper part.
Resistance map shows parts of a Roman Villa Rustica
Georadar is primarily used when not only the position of objects and structures, but also the depth of the objects should be determined. The measurements are used for the detection of shallow cavities, tunnels, graves, trenches and wall- and foundation structures. Even the detection of larger objects made of metal, such as buried tanks, barrels or metal pipes can be identified by georadar.
The radargram shows the result of measurement above a Roman Villa Rustica with visible hyperbola. These reflection hyperbola indicate artificial underground structures like wall remains. Position and depth of the walls can be identified and a determination of the building expansion can be carried out by measuring other profiles.
Reflection hyperbola show the position and depth of wall remains which belong to the Roman Villa Rustica