Geophysical survey at Khramis Didi Gora

Institute of Earth Sciences and National Seismic Monitoring Centre, Ilia State University. 

Principle of Geo-Radar Operation

GPR (Ground Penetrating Radar) (under ideal conditions) provides results that are kinematically equivalent to those of seismic exploration methods. The transmitting antenna emits a pulse of electromagnetic waves into the ground, where, similar to seismic waves, it is reflected, refracted, or diffracted, primarily due to changes in propagation velocity. These waves scatter and return to the ground surface, where the receiving antenna records them. The signal is then amplified, digitised, and stored for further analysis and processing. 

Typical GPR frequencies range from 10 to 1000 MHz, and the velocity of electromagnetic wave propagation in the ground amounts to 0.25-0.5 of the speed of light (0.05-0.14 meters per nanosecond). The propagation velocity of GPR waves decreases as relative dielectric permittivity increases, while wave absorption (attenuation) increases with higher electrical conductivity. 

Dielectric permittivity defines a material’s ability to store electrical charge when an electric field is applied, which is analogous to the modulus of elasticity in seismology. High conductivity causes electric current flow and thus dissipates energy, absorbing the wave.