Geophysical Explorations

Subsurface and structural exploration using various geophysical methods for geological and hydrological issues, raw materials, mass movements, archaeology, cavities, landfills, dams, etc.

Depending on the method used, geophysics is used to determine various physical parameters of the subsurface. This allows information about the structure and composition of the object under investigation to be derived. The measurements are aimed both at artefacts and at the general composition of the ground, such as the geological structure, groundwater level, installations or cavities. Other areas of application include the detection of tree roots, animal burrows and the inspection of structures such as dams, buildings or the inner lining of tunnels.

The investigation of the subsurface consists of two work steps:

• Geophysical measurements.
• Evaluation and interpretation of the measurements.

Depending on the issue at hand, the following geophysical measurement methods are used:

• Geoelectrics and Electromagnetics: Determination of the electrical resistance or conductivity of the subsoil along profiles or over an area up to a maximum depth of 300 metres. Geoelectric monitoring (incl. inclinometer) for monitoring mass movements or dams, for example, is also available.
• Magnetics: Deviations from the total field of the Earth´s magnetic field due to ferrous objects or deposits in the subsurface. Profiles or areal measurements up to a depth of several kilometres.
• Seismic: Determination of the propagation speed of seismic waves (caused by e.g. drop weight, hammer or blasting) along profiles, which provide information about the soil layers, bedding conditions or rock qualities.
• Ground Penetrating Radar: This electromagnetic method (transmission frequencies between 80 and 1,000 MHz) can be used to detect layers, cavities and installations as well as pipes down to a depth of approximately 10 m. The measurement is carried out along profiles as well as over large areas with multi-channel systems and a resolution of 6 x 6 cm to 10 x 50 cm.
• Radiometry: Determination of natural radioactive radiation on the Earth´s surface caused by potassium, uranium and thorium.
• Borehole geophysics: Most of the methods described above can also be carried out by drones or in a borehole.

The measurement data is processed using special software packages and the measurements are converted into interpretable variables (inversion). The interpretation is then carried out together with the client and geologists, hydrologists, archaeologists, etc., depending on the issue at hand.