Ground-penetrating radar is most commonly used to determine:

• A. Volume of groundwater
• B. Depth to bedrock
• C. Locations of buried objects
• D. Rock porosity

Answer: (C)

Ground-penetrating radar works by sending radio waves into the ground and listening for reflections produced when those waves encounter a change in dielectric properties. Buried objects such as pipes, cables, tanks, or voids create strong contrasts with surrounding soil, causing distinctive echoes that show up clearly on the radar data. Because this setup makes it easy to detect and map the position of these objects, locating buried items is the most common and practical use of GPR.

While GPR can sometimes help estimate how deep bedrock is in favorable, low-conductivity soils, penetration depth is highly sensitive to soil conditions like moisture and clay content, so bedrock depth isn’t as reliably determined or as widely used a purpose. Groundwater volume isn’t directly measured by GPR, and rock porosity isn’t something GPR provides a direct, simple measurement for; those typically require other methods or interpretations.