Terror Beneath the Ground: Unlocking the Whys and Hows on Italy's Earthquake
A powerful 6.2 magnitude earthquake that devastated Amatrice, Italy last Wednesday morning is the result of Italy's complicated geology, shallow quake and century-old buildings.
Live Science reported that the earthquake, which killed at least 73 people and destroyed the postcard-worthy old buildings, had its epicentre about 6.2 miles (10 km) southeast of Norcia. The earthquake was so strong that the intensity was felt even in Rome, which is 70 miles (112 km) southwest of the city.
Italy is earthquake-prone due to the complexity of their geology, and this proves to be fatal. The Washington Post reported that below Italy's Apennine Range, there is a "tangle of fault lines and fractured rock." The mountain range was formed 20 million years ago due to the African plate "plowing" into the Eurasian, crushing the crust. Every year, the crust in the northern range moves away from the south at a rate of three millimetres, causing the earth to tremble along with the minor fault lines.
With this in mind, it is enough to say that this is a recipe for a disaster. Now, the question stands: how this affected the recent earthquake?
Julie Dutton, a geophysicist at the U.S. Geological Survey, said that the African and Eurasian plates that are in northeastern Italy collided slowly, which made the ground below the Alps to shove up. Despite causing the ground below the Alps to move up, the quake didn't necessarily cause it. The continental plate collision zone "is drifting southeast, and it is stretching the crust beneath a region of the Mediterranean Sea."
Now that the tremor is in deep Mediterranean Sea, it now moved the Tyrrhenian Basin, which is a seismically active area of the Mediterranean Sea. The ground in this area "is actually spreading apart," Dutton said to Live Science. This activity creates a tension that reached the Aps, which started the fatal earthquake.
The New York Times notes that partly to blame with the severity of the damag is the fact that the buildings, houses and street lamps in Italy are more than 100 years ears old. Thus, resulting to more rubble with thousands of homeless, trapped and killed civilians.
"Even 100 years ago, they didn't know how to build structures to withstand earthquakes," said David A. Rothery, professor of planetary geosciences at the Open University in Milton Keynes, England.
Compared to recent earthquakes, Italy's quake shouldn't be so destructive if it only wasn't as shallow. The United States Geological Survey said that Italian quake occurred about six miles below the surface.
"Shallow earthquakes cause more destruction than deep earthquakes because the shallowness of the source makes the ground-shaking at the surface worse," Rothery said.