Sixteen shocks of linear magnitude 2 (Richter scale) or higher in the regional territory from Tuesday, August 4 to Sunday, August 16 according to the page www.regione.toscana.it/-/terremoti-in-toscana, practically more than one shock per day. Put this way, it would look like a coincidence, but coincidences have no place in science. We therefore ask for an explanation from Carlo Meletti, a seismologist with almost forty years of experience and a historic mainstay of the Pisa section of the Ingv.
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Is there a correlation or is it just appearance?
“In reality, the shocks detected by the Ingv were overall about fifty. The discrepancy with the Region’s portal is that the agency must have set a minimum magnitude, while we also record those with a magnitude below 1.”
He lists them with “calmness”. What are they due to?
“These are what are commonly referred to as aftershocks, while for us they are “replicas.” They are largely manifestations following the August 4 episode in Pisa: the energy accumulated by the system was released causing the earthquake, then there was the other shock on Wednesday, also in the Pisa area. It is returning to a calm situation.”
Is the shock recorded on Sunday, August 16 in Fosdinovo somehow connected?
“We are talking about two very different and incomparable contexts. Lunigiana is a well-known seismic zone with experience of much stronger shocks compared to the Livorno-Pisa area, where the maximum magnitude ever recorded in recent times was 4.6 in 1986.”
It was August then too. Does the saying that heat causes earthquakes therefore have a basis?
“My grandmother used to say that too. But just recently I went back to read our historians and I can safely say that earthquakes come both with heat and cold, more or less in equal intensity and measure.”
Are there anthropic factors that may have influenced? Is it “our fault”?
“On our social media, some even claim that earthquakes are caused by “too many bombs.” But these are events that take place 8-10 kilometers deep, and down there nothing that happens in the atmosphere has any influence. An atomic bomb (or something more powerful), that would be another story.” Faced with these “theories” the only thing we can do is respond with data and science.”
In this sense, can what is happening in Tuscany have a positive value?
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“Certainly yes, it is a source of very precious data. We must consider that an earthquake cannot be reproduced in a laboratory. Each shock therefore helps us understand which faults break and consequently to plan, indicating for example the areas where not to build.”
Will it also help us predict future earthquakes? Maybe thanks to artificial intelligence?
“Based on our knowledge, predicting earthquakes is not possible. We already use artificial intelligence, and many (non-scientists) ask us for our data to train new models. Certainly AI is “good” at analyzing data series and maybe can indicate the direction to look at, but Italy’s conformation is very complex.”
So what should we expect in the coming days? At least in the Livorno and Pisa area.
“Our historians tell us that the return to calm was observed over a period of about a month. The earthquake was on August 4, the next strongest shock was on the 12th: judging by the trend we are recording I would say the phenomenon is ending.”
And in the future?
“Geological times are immensely longer than a human life. The system will start accumulating energy again until the next breaking point, that is the next earthquake. But for now we can be calm.”
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