The Tyrrhenian Basin, or Sea, which lies to the west of Italy, between the mainland and Sardinia/Corsica, is slowly opening up. Scientists say this is contributing to extension, or “pull-apart”, along the Apennines which works at a rate of 3mm per year. Add in movement in the Adriatic where the crust is rotating in an anti-clockwise direction, and you have a fiendishly complex picture. Italy is literally being pushed and pulled every which way.
“The Apennines are also very high; the crust is very thick there and there’s a process of gravitational collapse,” said Dr Richard Walters from Durham University, UK.
“So, there’s a spreading of the Apennine mountain chain which also then leads to extension – the pulling part – and therefore the normal faulting earthquakes.”
“The effects are so devastating here because the quakes happen so shallow in the crust. And that’s just due to the nature of the faults,” explained Dr Laura Gregory from Leeds University, UK, who works in the region.
“They’re really quite small faults but because they’re shallow, the shaking is very dramatic right above where the quake happens.”
Quakes ‘ever present’ for Apennines, bbc.com