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Geophysical Services at EPI

What is Ground Penetrating Radar (GPR)?

Ground-penetrating radar (GPR) is a geophysical method that uses radar pulses to image the subsurface. This nondestructive method uses electromagnetic radiation in the microwave band (UHF/VHF frequencies) of the radio spectrum, and detects the reflected signals from subsurface structures.

HOW does GPR work to detect underground utilities? 

Ground Penetrating Radar (GPR) is one of the most effective technologies used in geological surveys, construction, environmental studies, and re-construction projects. With GPR, we get real-time visuals of facilities that can't be located by traditional methods. 

  1. Location. GPR locates underground storage tanks, concrete structures, buried manholes, septic tanks, water and sewer lines, unmarked grave sites, and more.

  2. Safer. GPR is a safer and less destructive means of locating buried utility lines.

  3. GPR sends electromagnetic waves into the ground, which are then reflected by subsurface structures or utilities and detected.

What are the benefits of GPR?

Once one of members from our geophysical team has located your underground utilities, we can map the ground markings using our GPS equipment for extreme accuracy. EPI uses uniform color codes for the marking of underground utilities.

  1. Reduce costs. Keep track of your facilities, prevent damages, and reduce costs on future planning and construction projects.

  2. Fulfill requirements. Fulfill regulatory requirements of GIS accuracy.

  3. Ensure accuracy. Our professionals are trained and certified to ensure extreme accuracy.

How deep into the surface can GPR go?

In most cases an estimated depth range can be determined with accuracy based upon the subsurface material and the frequency of the GPR antenna. For applications requiring higher resolution, such as locating rebar or conduits in concrete, a higher frequency GPR system (1,000 MHz) is used. 


This will give high resolution detail for down to approximately 24 inches in depth. Applications which require deeper penetration in ground soil requires a lower frequency (12.5 MHz to 500 MHz). Depending on the subsurface material the depth range can be from a few inches to thousands of feet

(Chart attached here).

Can GPR be utilized through water?

Yes. GPR can be utilized through fresh water, but it does not operate where salt water is present. Also, GPR works extremely well through ice and snow. They are some of the most favorable conditions for GPR.

Interested in a free GPR demonstration?

At EPI, we offer free GPR presentations. EPI's geophysics manager and professor, Paul McLeod will come to your office to explain the benefits of GPR and demonstrate how EPI can help you and property owners save money and avoid the awful experience of striking, and likely damaging, buried utilities that would've been unknown without using GPR. 

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