Frequently Asked Questions

GPR can work through fresh water and even ice and snow; and with the right expertise, GPR can be used to identify the location of water leaks from pipes, for instance. However, the technology does not work in salt water due to its high conductivity, which severely attenuates the strength of the signals.

To conduct a GPR survey, you need two main pieces of equipment, a transmitter and a receiving antenna. The transmitter emits pulses of electromagnetic energy into the ground or other surface being surveyed. When the pulse hits an object or a variation in the composition of the ground material, the density of that object reflects, refracts or scatters the signal. The receiving antenna then records these variations in the signal to build up a profile of the surveyed area. That data is then interpreted by an expert to form an opinion of the composition of the subsurface and any objects that lie within it.

Yes, voids that are either air or water-filled below a road surface, for instance, can be detected with GPR. These voids are typically caused by erosion or subsidence in the base and subgrade materials. They present potential dangers as they can eventually lead to cracking and can reduce the load carrying capacity of the road’s surface. The technology allows for the identification of areas below the surface where the physical properties of the ground change. Accurate analysis of the results of a GPR survey can detect the extent of the void and whether it is air- or water-filled, so that the appropriate remedial action can be taken.