Geophysical methods are used for carrying out non-destructive structural investigations and diagnoses. The methods reveal with high resolution the internal structures of civil engineering works as well as the constructional elements. Such surveys range from analyses at discrete points, to measurements on lines and grids, and even full volume investigations.

The possible applications are manifold and can be used for both mineral as well as organic building materials, for example:

• Supports, foundations and pillars
• Walls, ceilings and floors
• Tunnel (inner) linings
• Road surfaces and runways
• Dams and dykes
• Excavations

Besides the classic measuring of thickness, the provision of proof of installation as well as a comparison of how the construction should be to what it is actually like, it is possible to recognise extremely well the inner structure of civil engineering works and in particular any damage or deterioration that has occurred. The wave-based techniques used, such as radar and seismics, can supply a resolution in the range of centimetres.