Ground Penetrating Radar

Ground Penetrating Radar (GPR) is a geophysical technique that detects reflected signals from subsurface structures. GPR uses high-frequency radar pulses that are directed into the ground to image subsurface structures. The signal consists of electromagnetic radiation in the microwave band (UHF/VHF frequencies) of the radio spectrum. When the directed waves encounter subsurface objects or boundaries with different dielectric constants, the receiving antenna records variations in the reflected return signal. Subsurface features both natural and manmade may be detected and identified.

GPR is ideal for fast, high resolution, shallow subsurface investigations. Data are collected in lines using a rolling cart. This data can be reduced and displayed individually for a 2-D profile, or multiple, parallel lines can be stitched together and reduced for a 3-D result and interpretation. Since the system is self-contained and transported in a cart, GPR surveys can be conducted in areas that are inaccessible for array-type geophysical methods. Reporting can be as minimal as spray paint or flagging in the field denoting the targeted structures or elaborate as full written reports including 2-D profiles or 3-D interpretations of the collected data.

This versatile method is ideal for locating and delineating underground utilities, shallow subsurface voids from karst or settlement beneath concrete or asphalt, underground storage tanks (UST's), archaeological structures, or general shallow geology mapping. GPR can provide relatively quick, efficient 2-D and 3-D surveys of a site where space is limited or even within existing buildings. It can be used as a stand-alone survey technique or combined with any of our other geophysical services to provide a more detailed, more robust interpretation.