The nation's strongest quake since 1980, Italy's latest earthquake may have long-term consequences for fault lines.
A 6.6-magnitude earthquake rocked central Italy Sunday morning, and is believed to be the strongest quake to hit the nation in decades.
The earthquake at about 7:40am local time was centered near Norcia,
Italy, a town in the Perugia region about 150 kilometers northeast of
Rome. Aftershocks were reported as far away as Venice. The quake brought
down several buildings but no deaths were reported; many had evacuated
(25 thousand are now reportedly displaced) after the area experienced a foreshock of a lower magnitude.
Heartbreaking. Landmark Basilica of St Benedict before and after the earthquake this morning.
Heartbreaking. Landmark Basilica of St Benedict before and after the earthquake this morning.
Italy's Prime Minister Matteo Renzi called the quake "the strongest
since the Irpinia one," a 6.9 magnitude earthquake in southern Italy in
November 1980 that killed some 3,000 people.
An earthquake of a comparable magnitude hit the region in August, killing more than 300 people.
Though the damage caused by the most recent quake is less significant
than that of the August quake, the tremors could still mean disaster
for the region.
An Italian news
channel posted this video, with the caption: "This morning's strong
shock has crumbled Norcia's iconic buildings."
The cause of the earthquakes is well known. The faults that run
through Italy are moving apart at a speed of three millimeters per year.
This causes insecurities in the fault, as evidenced by the recent
earthquake. (Read our earthquake explainer.)
The August quake damaged two nearby faults, Laga and Vettore. The
latest earthquakes have further broken portions of the Vetorre fault,
but it remains to be seen how deep the damage goes.
If the latest tremors damaged deeper portions of the vault, the extent of the damage may not be evident on the surface.
"This would be what we call 'depth segmentation' where the shallow
portions break followed by the deeper portions. And it means you can
have an earthquake repeating more frequently on the same faults," Dr. Richard Walters, an earth sciences lecturer at Durham University in the UK, told the BBC.
Experts are monitoring the sites for changes. They will be taking
series of satellite images and comparing them to images from before the
quake in an attempt to determine whether there have been any major
geologic shifts.
If the faults have indeed been damaged on a deeper level, the number of earthquakes could increase dramatically.
http://news.nationalgeographic.com/2016/10/italy-earthquake-norcia-fault-future/
http://news.nationalgeographic.com/2016/10/italy-earthquake-norcia-fault-future/
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