Earthquake in the province of L'Aquila, at least 70 shocks in the night: Unpredictable seismic swarm


After the 4.4 magnitude earthquake recorded yesterday in Balsorano, in the province of L'Aquila and at the border between Lazio and Abruzzo, at least one occurred seventies of new shocks in the night and until this morning. To confirm it to it was Alessandro Amato, research manager of theIngv, the National Institute of Geophysics and Volcanology. "After the earthquake of greater intensity, the reply the magnitude 3.5 shock was stronger shortly after midnight, while the others, which were reported in the tens, have not reached magnitude 2 and therefore they turned out to be imperceptible to the population, "the expert stressed. The latest shock in temporal order was felt today, Friday 8 November, at 11.43 am always with Balsorano epicenter: the magnitude was 2.6 and at a depth of 13 kilometers. It is therefore a question of one earthquake swarm which has already begun for a few days and whose evolution is unpredictable.

"Swarms like this can start with smaller shocks – Amato pointed out – and then continue with stronger events in hours or days, to then decrease or increase again. This is their characteristic variation over time which makes them particularly unpredictable, unlike sequences that start with a major shock and then have a decay in the number and magnitude in the following days. In this case, it all started with weak earthquakes, followed by a stronger shock, the one recorded last night at 6.30pm. And now we are witnessing other small replicas that we don't know how long they will last. Surely there will be in the next ones, but it is impossible to give estimates of how many there will be and of what intensity ".

The earthquake that is shaking the area on the border between Abruzzo and Lazio, however, has nothing to do with the earthquake of Amatrice in 2016 and that of L'Aquila in 2009. "Let them be systems of faults different is now quite clear because they are distant and do not have a direct connection – explained the expert of Ingv -. However, they have similar characteristics with respect to the type of movement and therefore of the earthquake generation mechanism. We call them direct faults, which respond to the same process of extension of the Apennines and which therefore enlarge the earth's crust. The latter with their epicenter in Balsorano are deeper than those recorded for example in Amatrice, here we are on 14 kilometers and in general the deeper the greater the area of ​​resentment ". This explains, therefore, why yesterday's earthquake was warned up to Rome and even to the provinces of Caserta e Naples. The situation, however, remains under control: "We monitor the evolution of this sequence which is currently confined to a few kilometers, it is a very small area on the border between Lazio and Abruzzo. We are keeping an eye on whether displacements can occur on other faults that could somehow give a different interpretation of the phenomena, "concluded Amato.

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