A huge 10 metre (33 ft) deep sinkhole has appeared in a suburb of Naples, Italy, following a water pipe that broke, causing the road above it to collapse.
The crater led to the evacuation of nearly 400 residents as the authorities hurried to cordon off the area.
It started off as a fairly large typical road pothole a few days ago. However, the leaking water pipe combined with heavy rains led to the ground subsiding significantly, creating a large crater.
When the land collapsed there was a “loud thud”, a female resident said. (Image: Il Mattino)
According to Il Mattino, a local newspaper, no buildings nearby have suffered any structural damage, but 380 people had to be found emergency accommodation in what local authorities described as a “precautionary measure”.
A female resident said she heard a loud thud at about 5am, looked out and saw a car falling into the chasm.
Civil engineers say the hole will be filled with concrete after it has been inspected and cleared of any further potential damage.
What is a sinkhole?
A sinkhole can be any hole in the ground resulting from erosion and the drainage of water. Some are just a few feet across, while others are big enough to engulf large buildings.
Most sinkholes are the result of natural processes, but human activity can also trigger them.
There are two basic types of sinkholes: 1. A cover-subsistence sinkhole – it evolves gradually over time. 2. A cover-collapse sinkhole – it appears suddenly.
While understandably the sudden ones create headlines, both types are formed by the same basic mechanism.
Sinkholes are more common in areas of land where soluble rock such as gypsum or limestone can be dissolved by water.
In the case of cover-subsidence sinkholes, the bedrock becomes exposed and over time is eventually worn down, with the holes usually filled with water (they become ponds).
The same happens with cover-collapse sinkholes, but nobody sees what is developing under the ground.
AP Video – Burst pipe causes sinkhole in Naples