Scientists discover fault line thought to have caused the earthquake that damaged the Colosseum
Scientists believe they have found the tectonic fault line which caused an earthquake that damaged the Colosseum and other buildings in Rome 1,500 years ago.
It is the same fault line that was responsible for a powerful quake three years ago that devastated the mountain town of Amatrice and surrounding villages, killing 300 people.
The fault system is located on Monte Vettore, a mountain in central Italy that is part of the Apennine chain.
Scientists excavated trenches around the fault line in order to expose sediment layers and to find out whether there had been tectonic shifts in the past, leading to earthquakes.
By analysing the strata, they discovered that the fault line on Monte Vettore had caused major earthquakes roughly every 1,800 years.
There have been six major tectonic events in the last 9,000 years, they found.
One of those quakes occurred in the fifth century AD, the sediment layers showed.
The researchers matched it with an earthquake that struck Rome in AD 443, when the Colosseum was damaged as well as a basilica and a number of early churches.
References to the repairs that were done to the buildings are contained in the writings of two emperors, as well as Pope Leo I, who reigned from 440AD to his death in 461AD.
The earthquake was felt as far away as Ravenna on the Adriatic coast, according to contemporary chronicles.
The discovery that the Monte Vettore fault line had caused several earthquakes in the past suggests that the 6.2 magnitude Amatrice quake in August 2016, which was followed by another quake in October, was not as surprising as first thought but part of a well-established pattern.
Other fault lines that are apparently dormant in the Appenines may very well erupt back into life, the scientists believe.
“In hindsight one could say that the 2016 earthquake was not so unexpected as previously supposed,” said the research team, led by Paolo Galli, a geophysicist at Italy's National Civil Protection Department.
Italy is one of the most seismically active countries in Europe, lying at the southern edge of the Eurasian tectonic plate, which rubs up against the Adriatic and African plates.
The findings were published in the American Geophysical Union journal Tectonics.
