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How does ground-penetrating radar help archaeologists find buried features?

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Archaeology Archaeologists mapping their finds at Pachacamac, Peru, an Indigenous town occupied from approximately 200 bce to 1532 ce, when it was sacked by conquistadors under the command of Francisco Pizarro.

Ground-penetrating radar (GPR), also known as ground-probing radar, is a valuable tool in archaeology that allows researchers to detect buried features without the need for immediate excavation.12

How It Works

Unlike standard radar that reflects off the surface, GPR operates at lower frequencies—typically ranging from 5 to 500 MHz—which allows radar energy to penetrate the soil. When these waves encounter buried objects or subsurface anomalies, they are reflected back to the surface.1

Key aspects of this process include:
* Penetration and Resolution: By using wide-bandwidth signals, the system can achieve high resolution, allowing it to distinguish between closely spaced objects at depths of approximately 3.3 to 33 feet (1 to 10 meters) or more.1
* Portability: Because the energy is directed into the ground rather than radiated into space, these portable units can operate without causing interference to other users of the radio spectrum.1
* Application: Archaeologists use this technology to identify underground structures such as tunnels, walls, and other features, providing a non-invasive way to map sites before beginning a formal excavation.12