Currently, it is already possible to detect cavities in some contexts. Every year, the range of ways we have to detect cavities is wider and the reliability of the different methods increases.
Various geophysical methods help the speleologists to find underground cavities: low frequency (VLF) or high frequency (georadar) electromagnetic detection, micro-gravity, geo-electrical tomography or reflexion seismic. With these methods, one can discover underground anomalies that can be interpreted as cavities.
We are experienced with the application of all these methods and we collaborate with partners who give us access to all these measuring devices. Therefore, we are in a position to either directly provide services in this field, or to function as experts to evaluate the interpretations offered by private companies specialized in geophysical surveys, knowing that these companies may not be used to working in a karstic environment. However, it is not yet possible to locate cavities lying at depths greater than 30 m (except with huge cavities or in other particular conditions). Please be critical about what we are able to offer...
Please take a look at our activities related to this subject in research & development
Using an electromagnetic transmitter-receiver device, SISKA is able to locate natural or artificial underground galleries from the surface. The transmitter is placed in the gallery. The receiver is above the surface, where an operator searches for the place directly above the transmitter. This instrument (designed and sold by SISKA) is capable of finding out the precise depth of the transmitter in addition to knowing its XY horizontal position. In theory, the measurements can be taken up to depths of 200 m, but in practice, their accuracy diminishes beyond 100 m. The French national institute for industrial environment and risks uses this device to find the position of mines. >
More information: UGPS 1 167 Kb
(This presentation article is written by Jean-Marc Watelet, INERIS)
AGAP Quality – GEOFCAN applied geophysics to discover cavities and man-made structures 6-8 of November 2006, Franche-Compté university, geosciences department
See also: : Underground cavities & civil engineering