In September of 2008 a paper came out in the Journal of Applied Geophysics, which reported on a Ground Penetrating Radar (GPR) survey of the site of “Le Pozze” in Lonato, Northern Italy. Most of the findings were from the Roman period and include the discovery of a large villa and public building. The researchers estimate that the two structures combined extended over nearly 10,000 square meters of space.
Here is the stopper – the survey was done in 2004. It took four years until it appeared in a journal.
Developed in the 1970’s, Ground Penetrating Radar (GPR) uses radio waves to detect and map underground objects and soil/rock strata. In the last three decades archaeologists have made extensive use of the technology. It allows them to detect, map and analyze archaeological remains without putting a shovel into the ground.
How it works
The science behind GPR is complex and has been the source of plenty of headaches for archaeology students. A very basic explanation of the technology works like this:
The antenna of a GPR system shoots radio pulses into the ground. Each pulse travels through the ground as a wave.
Within the ground there are different layers of subsurface materials (soils, rocks and, hopefully, archaeological remains).
Every time this wave comes in contact with a new layer of soil or debris, the velocity of the wave changes. This causes some of the energy of the wave to “bounce” back as a reflected wave.
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It can provide a powerful and intuitive means of communicating complex information to non-geophysicists.