The quake hit about 470 miles (750 km) north of the plate boundary - the place where the two colliding plates meet - which runs along the sole of Italy's "boot."
It is here that the African plate is plowing slowly northward, crashing into the Eurasian plate.
Caruso explained that the shallower a quake, the more damage it can cause. "If a quake is 500 kilometers deep, and you're right on top of it, you're going to feel it a lot less strongly than if it's 5 kilometers deep," he said. "As the seismic energy moves through the ground some of it is dissipated."
The strong quake rocked an area with a long history of earthquakes, yet one that has kept relatively quiet for hundreds of years.
"There has not been a whole lot of action in that area," Caruso said. "The fact that they do have records of earthquakes going back a couple thousand years shows this area hasn't been seismically active for a long time," he said.
Thousands of people were displaced by the quake, and many people spent the night in tents hurriedly erected on soccer fields.