The world news on disasters in the last two months has been marked by a series of strong to moderate earthquakes in Italy.

The first incident was on 24 August 2016, Mw6.2 in Amatrice, claiming 295 lives and demolishing the city of Amatrice and its surrounding area.

Since August, the two more earthquakes with magnitude greater than 6 have occurred in the north of the Amatrice earthquake epicenter: 26 October 2016 in Visso, and 30 October 2016 in Norcia.

This zone with an approximate length of about 150km in north-south direction is an extensional fault zone between L'Aquilla, the epicenter of 6 April 2009, M6.3 earthquake with 300 victims, and Perugia.

Since Rome, the capital of Italy, is located about 140km to the west of this fault zone, most of the moderate to strong earthquakes over the last two months are felt in Rome as well.

The earthquake zone experienced another strong quake in 26 September 1997 in Perugia with about 300 victims.  

These five consecutive earthquakes, one in 1997 and 2009, and three in 2016, might be modeled as an “earthquake sequence” in a fault zone, 150km length, which took place in Perugia-L'Aquilla zone.

There is an interesting point in the last earthquake in the series: in Norcia, 30 October 2016, M6.7, which was greatest quake in Italy since 29 November 1980 - with M6.9 in Irpina (southeast Italy), that claimed 2,500 victims.

However, the latest earthquake in October 2016 near Norcia had no victims, because firstly, the time of the earthquake was at 10:10 a.m. local time. Therefore most of the inhabitants were up and outdoors.

Secondly, the occurrence of pervious earthquakes in that zone had brought awareness to public, expected the possibility of such quakes in the area.  Since the main shock of 24 August 2016, about 20,000 aftershocks, with a magnitude of M1.0 or greater, have been recorded in this region.

Thirdly, since the end of August, there had been a partial evacuation of this seismically active zone, making the area sparsely populated around the end of October.
 
Before the new series of earthquake, the town of Amatrice had a population of 2,600 people, but during the main shock of 24 August (occurred at 3:36 a.m.), about 10% of population was wiped out, some 290 people.

The town of Visso, with about 1,100 inhabitants, was almost totally evacuated during the 26 October 2016 earthquake.

The city of Nocia, with about 5,000 residents, also did not report any victim on 30 October 2016, because about 14,000 people had been already displaced from the region as mentioned previously.
 
It is worth noting that the seismic network of Italy is the most densely instrumented seismic network in Europe, with 640 seismographs.

The newly established “AlpArry”, launched on 1 January 2016, is comprised of 12 European countries, sharing 650 seismographs in the network, with Italy being an important participating state.

The new network, AlpArray, a European initiative to observe and monitor in detail the seismicity of the Alp Mountains, is aimed to understand the orogeny of the mountains and its relationship to mantle dynamics, plate reorganizations, surface processes and seismic hazard, not only in the Alps, but also in the Apennines, Carpathians and Dinarides mountains.

Since the earthquake sequence, from August to October 2016, has occurred in the southern parts of AlpArray, it is expected that the new earthquake sequence in Italy provide a great scientific resource (data) for seismologists’ studies.
 
This initiative integrates present-day earth observation with high-resolution geophysical imaging of three dimensional structure and physical properties of the lithosphere and of the upper mantle.

This newly established array might be taken as a model to develop new seismological dense network to be established in the Middle East, especially in Iran, in order to understand in detail the geodynamics of the Alborz, Zagros and Kopet Dagh mountains, and the seismic sources.

This array may provide a new source for modern seismology based on precise and well recorded data, marking the beginning of new era in the science of seismology in the 21st century.