Ground penetrating radar (GPR) provides a high resolution, cross-sectional image of the shallow subsurface. A short pulse of electromagnetic energy is radiated downward. When this pulse strikes an interface between layers of material with different electrical properties, part of the wave reflects back, and the remaining energy continues to the next interface. Depth measurements to interfaces are determined from travel time of the reflected pulse and the velocity of the radar signal.
The Ground Penetrating Radar (GPR) method relies on contrasts in the dielectric constant between materials. The methods have been used extensively to:
Map water table and bedrock topography
Map stratigraphic layers
Evaluate mine and quarry rock
Image geological structures, fracture and fault
Map the location and burial depth of drums, underground storage tanks, and utilities
Identify buried utilities and infrastructure
Delineate disposal pits, trenches, and landfill boundaries
Locate voids and washouts along pipelines, under roadways, parking lots, and building floors
Investigate the thickness of peat
Determine the existence of subsurface voids
Investigate archaeological sites and cemeteries
Screen proposed borehole locations for subsurface interference
Delineate inorganic and organic free-phase contamination plumes
