"Scientifically, no one in the world is capable of making a serious and verifiable prediction about exactly when an earthquake will hit," according to Enzo Boschi, speaking to the ADN Kronos wire service shortly after Monday's earthquake hit at about 3:30 a.m. local time. However, earthquakes can be anticipated right before they strike.
Early warning systems analyze data coming from networks of sensors in the ground and in water in geographic areas at high risk for earthquakes. These networks, or grids, send signals along fiber-optic lines to control centers.
Software is capable of managing information sent by the network during the very first seconds of an earthquake as fissures are formed at its epicenter. During a large earthquake, this permits alerts to be sent out a few seconds (or longer, depending on how far the alert is being transmitted) before the first shocks hit communications, transport and energy grids.
There are currently a number of projects to create early warning systems in Italy and around the world, . Having started just a few years ago, these projects have already helped improve alert systems, reducing the number of false alarms and enabling faster analysis by current warning systems.
Early warning systems have been refined thanks to, among other things, the incorporation of more advanced algorithms to decode signals coming from geological sensor grids. Some of the more advanced early warning systems in Europe fall under the aegis of the SAFER (Seismic Early Warning for Europe) project, an initiative backed by the European Commission.
Today, such systems can guarantee alerts about one to three seconds ahead of an earthquake within 10 kilometers (6.2 miles) of the epicenter, or 10 to 12 seconds within 100 km of the epicenter.
SAFER has financed such systems in Naples, Istanbul, Bucharest, Athens and Cairo.
The few seconds of warning provided by the SAFER systems obviously won't help to evacuate citizens in earthquake zones, but are indispensable for activating a series of automatic procedures that can help avoid, for example, interruption of natural gas supplies that could also cause explosions.
Undersea early warning systems can alert coastal inhabitants of impending tsunamis well in advance of when they strike. Early warning systems can warn Spanish inhabitants along the Gulf of Cadiz about 15 minutes before a tsunami hits, while in the Pacific Ocean alerts can be sent hours ahead of tsunamis.
However, even though the few seconds of warning before an earthquake hits would not necessarily help California inhabitants evacuate, "seconds are better than nothing," according to Richard Allen, a professor at the University of Berkeley. "Californians would have at least enough time to get under a table or someplace safe."
"It enables the fire departments, ambulance and health services to be alerted," he added.
Allen has developed a system, called , that sends out alerts to cell phones or computers to anyone subscribing, up to 10 seconds before a tremor hits. The experimental system is bring trialed at the California Seismic Network (CISN).
To refine ElarmS, Allen is tapping US$120,000 a year from the U.S. Geological Survey -- a lot less than funds available in Europe or Japan.
Allen's network has only 285 sensors, put in place in collaboration with CISN. By comparison, Japan has invested $35 million in a warning system comprising 1,000 sensors.
With traditional systems, it takes about five minutes to locate an earthquake's epicenter and evaluate its magnitude. Early warning systems, sending out alerts seconds before an earthquake hits, can give a slight but fundamentally important edge to authorities and local inhabitants.