Seismologists have always told us that preventing earthquakes is impossible. Although the Italian National Institute of Geophysics and Volcanology (Ingv) has advanced the possibility that it will be possible in the future to do so by observing the movement of fluids before a strong shock.
Italy, unfortunately, is also a highly seismic country. Placed as it is between Africa that presses from below and the detente of the Apennines towards the former Yugoslavia. In the last century, for example, there are seismic events such as that of Messina, in Friuli, in Irpinia, in the province of L’Aquila.
In the last 30 years alone, more than 190,000 events have been recorded by the National Seismic Network. A fifth of them has made significant inflictions on the affected areas.
Technology, and in particular the smartphones to which we are glued for hours a day, can however make its contribution. In fact, ShakeAlert, an earthquake early warning system, was created. Here’s how it works.
An app that warns in case of earthquakes
As reported by Il Fatto daily, ShakeAlert identifies and characterizes an earthquake a few seconds after it occurred. Calculating the possible intensity. Then it immediately sends an alarm to those who are in the affected area.
For now, the app that warns of earthquakes has been launched on an experimental basis on the west coast of the United States. Where 50 million people live.
It uses a network of 700 seismometers, capable of recording the P waves generated by the earthquake. P waves are compression waves, they generate volume changes along the direction of propagation and travel between 6.0 and 8.8 km / s (kilometers per second).
S waves, on the other hand, are transverse waves, which cause shape variations in rocks and oscillate from the bottom up. Their propagation speed is between 3.6 and 4.7 km / s.
The L and R waves are surface waves and are the ones that shake the ground, causing damage and destruction. The former have a propagation speed between 2.0 and 4.5 km / s and shake along the horizontal plane. Rayleigh waves, R precisely, move along the direction of propagation and along the vertical plane. They are about 10 percent slower than Love’s.
In light of this, the P waves are, albeit slightly, the fastest and “arrive” first to the seismographs. However, let’s talk for a few seconds. And, of course, the further you are from an epicenter, the more effective the alert will be. As there will be more time.
ShakeAlert therefore cannot tell us that an earthquake is coming. But it can tell us that tremor is in progress or that it just happened. Thus, it can give time to escape, stop a train, a plane, suspend surgery, close an elevator, and so on.
Of course, Italy is still in bad shape with regard to exercises in the event of an earthquake. So something like this could create panic and make the mass irrational. Therefore, such a technology must be studied in the best possible way before it is actually made operational.
Also because it will always have a margin of error. What happens if it raises the alarm for something that did not actually occur? Also because, if you have noticed, earthquakes often occur at night. Here I have outlined the possible reasons.