The Earthquake has struck again. Central Italy again. Three strong tremors of magnitude greater than 5 in one hour, from 10.25 to 11.25. A quarter of the same entity at 14.34. And the country is once again afraid. "Four months after the earthquake of magnitude 24 of last August 6, the seismic sequence in central Italy exceeded 40.500 shocks, affecting Lazio, Umbria, Marche and Abruzzo".
The tremors affected an area that has always been under observation because it is considered by insiders to be at high risk.
Italy, on the other hand, is known precisely for being a country with a high seismic risk. Areas such as Sicily, the Eastern Alps and towns and cities located along the central-southern Apennines, from Abruzzo to Calabria will always be subject to earthquakes due to the geological nature of our territory.
Precisely to try to better understand the seismic danger of the Peninsula, and therefore prepare adequate countermeasures aimed at promoting prevention, in 2006 the map by the National Institute of Geophysics and Volcanology INGV was published in the Official Gazette of the State, designed and approved following the tragedy that struck San Giovanni di Puglia a few years earlier.
In fact, in 2002 the Civil Protection ordered an in-depth reclassification of the national territory from which the map (which we present in the photo) arose, a document implemented by the Regions which, on the basis of it, should have reclassified their own area of belonging, an operation which however it was never fully completed. Since 2015, a new map has been being drawn up which will be presented in the first months of 2017 and will integrate the data collected over the decade.
Generally speaking, since 2002, Italy has been divided into four zones based on the classification provided by INGV:
– Zone 1 – It is the most dangerous zone. Strong earthquakes can occur
– Zone 2 – Strong earthquakes can occur in this area
– Zone 3 – Strong but rare earthquakes can occur in this area
– Zone 4 – This is the least dangerous zone. Earthquakes are rare.
The seismic hazard map created by Ingv is based on the maximum expected ground acceleration resulting from seismic waves (S) in rigid homogeneous sounds, within a depth of 30 meters.
