Dec. 3 (UPI) -- Tunnels under Rome are being mapped by geoscientists in an effort to prevent the structures above from collapsing into the void below.
The elaborate labyrinth of quarries and tunnels below the streets of Rome is well known among locals. In 2011, 44 structures or portions of streets collapsed into these quarries, with the number rising to 77 and 83 in 2012 and 2013 respectively.
George Mason University scientists Giuseppina Kysar Mattietti and scientists from the Center for Speleoarchaeological Research in Rome are mapping the tunnels to prevent such incidents, and also because most Romans have taken it upon themselves to patch up these quarries.
"The most common way is to take some big plastic bags and fill them with cement and stick them in the holes," said Kysar Mattietti.
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Kysar Mattietti and her colleagues are using 3D mapping to check the structural integrity of the tunnels and even mapping them by hand. The tunnels are in various stages of degradation and the local government is hoping to have a map of risky areas so that repairs can be made as needed.
The land on which Rome was built is made up of volcanic rock, and the city's earliest architects used the rocks because they were strong and easily carved into building blocks.
Outside the city scientists found that even when the suburbs began to encroach over the quarries, the tunnels were narrow enough to support the ground above it.
Environmental factors and excessive quarrying made these tunnels wider and incapable of supporting the ground above. But once quarrying ended they turned into a kind of catacombs, used for mushroom farming and as an unofficial sewer system, among other things. During World War II, people used the tunnels as bomb shelters.
[Scientific American]
