Devastation: An aerial view of the area around the Abruzzo capital L'aquila, epicentre of an earthquake which struck early on 6 April. The violent temblor jolted central Italy killing at least 150 people and injuring 1,500 as buildings and homes in the walled medieval town were reduced to rubble.
Credit: AFP/CORPO FORESTALE DELLO STATO
All this results in "complex tectonics," said John McCloskey, a professor of geophysics at the University of Ulster, Northern Ireland.
In the case of the Apennines, the problem is so-called normal faulting, in which a brittle crust being is pulled by a subterranean sideways movement, prompting the fault to rip open along an inclined angle.
The region could be hit by powerful shocks in the coming months, as the energy released by Monday's event places further stress on neighbouring faults, McCloskey feared.
Brittle crust
"Earthquakes like this frequently trigger other earthquakes in the region. After the Umbria and Marche earthquakes there was a sequence of eight events higher than magnitude five in the following two months," he said.
He referred to two deadly quakes in September 1997, around 100 km to the northwest of Monday's quake, that had a magnitude 5.6 and 6.0.
Musson said it was "quite possible" there was a structural link between the 1997 and 2009 quakes.
Seismologists have becoming increasingly interested in the concept of a domino effect after the 26 December 2004 earthquake that unleashed the Indian Ocean tsunami and was followed by other massive temblors along the same fault west of Sumatra.
