Complete ancient Roman city mapped using ground-penetrating radar
An international team of researchers has mapped the entirety of an ancient, buried Roman city known as Falerii Novi using radar scanning technology. The researchers unraveled the secrets of the city, which once sprawled over 30.5 hectares of Italian countryside 50 km (32 miles) to the north of the Roman capital, by riding over its buried remains in a quad bike towing a ground-penetrating radar instrument.
By using new technology, archaeologists are able to unravel the secrets of ancient civilizations whose culture has had a dramatic influence on the world we see today with a level of detail and scope that was hitherto unimaginable.
Often, the passage of time and the relentless march of human advancement works to obscure the relics of the past in ways that make it difficult for modern day scientists to unearth. New buildings are built over existing archaeological sites, and over time once great cities become lost to the soil upon which they once rested.
Archaeologists now combine traditional field work with advanced technology to uncover the secrets lost to the ground. An incredibly useful tool at the disposal of history junkies is ground-penetrating radar (GPR).
GPR instruments essentially work by firing radio waves capable of travelling through matter into the ground. These waves bounce off objects or structures buried beneath the surface, and travel back toward the instrument. By recording the characteristics and timing of the returning waves, scientists can build a picture of ancient relics and unknown buildings that would otherwise lay hidden in the earth beneath our feet.
Recent improvements to GPR technology have allowed scientists to make wide scale surveys of archaeological sites that complement the more detailed observations achieved by carrying out traditional site excavations.
For the new study, archaeologists surveyed all 30.5 hectares of the walled Roman city by driving over its buried remains in a quad bike towing a GPR instrument. The team collected an impressive 71.7 million readings equating to roughly 4.5 GB of raw data per hectare.
It is thought that the city was founded in 241 BC, and remained occupied throughout Roman times up until around 700 AD. It has already been the subject of numerous archaeological investigations, yet the new high-resolution study managed to reveal a number of structures present within the city boundaries that had previously lain undiscovered.
The team identified a columned temple located to the west of what once was the south gate of the city, an impressive bath complex and a market building.
Whilst these building are commonplace across the roughly 2,000 cities that populated the Roman world, some of the specimens outlined in the Falerri Novi data appear to be unusually elaborate in their design, especially considering the size of the city.
The radar mapping revealed a vast enclosure spanning 90 x 40 m (295 x 131 ft), which on three sides was defined by covered passageways boasting central columns, located to the east of the north gate. Within this complex a pair of structures faced each other. The researchers believe that the enclosure was once a vast public monument.
To the south, just inside the city walls, the team identified a large rectangular building adjacent to the baths. The detailed observations showed that the building was connected via a network of pipes to the city aqueduct, and that these pipes ran underneath city blocks rather than through the streets, as would have been expected. The pipes suggest that the building was likely an enormous open-air pool known as a natatio.
The data also suggests that the city fell victim to stone robbing at some point in its history, wherein floors, surfaces and in some cases entire walls that once existed have been entirely removed.
Due to the massive amount of data harvested during the study, it will be a long time until the researchers are done analyzing Falerri Novi. It currently takes around 20 hours for a person to manually document a hectare’s worth of observations. However, the authors believe that, using new automated techniques, the work could be completed faster, and that GPR observations have a promising future in archaeological study.
"It is exciting and now realistic to imagine GPR being used to survey a major city such as Miletus in Turkey, Nicopolis in Greece or Cyrene in Libya," comments the study’s corresponding author, Professor Martin Millett from the University of Cambridge's Faculty of Classics. "We still have so much to learn about Roman urban life and this technology should open up unprecedented opportunities for decades to come."
The paper has been published in the journal Antiquity.
Source: University of Cambridge