What Is GPR?
This nondestructive method uses electromagnetic radiation in the very high, ultra high and microwave frequencies of the radio spectrum, and detects the reflected signals from subsurface structures. GPR can have applications in a variety of media, including rock, soil, ice, fresh water, pavements and structures.
The concept of radar is familiar to most people. With ground penetrating radar, the radar signal – an electromagnetic pulse – is directed into the ground. Subsurface objects and stratigraphy (layering) will cause reflections that are picked up by a receiver. The travel time of the reflected signal indicates the depth. Data may be plotted as profiles, as maps isolating specific depths, or as three-dimensional models.
Ground-penetrating radar is a reliable solution for locating underground utilities. Standard electromagnetic induction utility locating tools, require utilities to be conductive. These tools are ineffective for locating plastic conduits or concrete storm and sanitary sewers. Since GPR detects variations in dielectric properties in the subsurface, it usefull for locating non-conductive utilities.
GPR can be used to perform a comprehensive environmental assessment of the subsurface. Environmental hazards such as soil contamination, underground storage tanks and drums can be easily seen using this non-intrusive method. The delineation of landfills, pathway contaminant flow and water table mapping can all be done using GPR.
Ground penetrating radar survey is the best method used in archaeological geophysics, because it can be used to detect and map subsurface archaeological artifacts, features, and patterning.
A powerful tool in favorable conditions (uniform sandy soils are ideal),GPR like other geophysical methods used in archaeology (and unlike excavation) can locate artifacts and map features without any risk of damaging them. Among methods used in archaeological geophysics it is unique both in its ability to detect some small objects at relatively great depths, and in its ability to distinguish the depth of anomaly sources.
Military / Border Patrol (Security):
Military applications of ground-penetrating radar include detection of unexploded ordnance and detecting tunnels.
GPR can be used to determine mining safety, finding bedrock and sand depth, gravel layers, rock quality and also determine mineral content.