ROME - A few seconds in advance. This time, the earthquake knocked on the door before you get there, but with a margin so short as to instill doubts about the usefulness of the system of "early warning" for which Japan is at the forefront since 2007. Thanks to technology "early warning" Many Japanese have received an alert on your mobile phone between 8 and 60 seconds before the shock.
TV and radio programs were interrupted to broadcast the alarm. The high-speed trains, obedient to the orders transmitted by computer, have slowed down and stopped to avoid derailment. Yet, incredibly, the network of 'early warning "were not linked to nuclear power plants. The implants are considered so important that it deserves a special network, which in fact was still being tested when the earthquake struck on Friday.
Not much better was the tsunami warning. On the beaches closest to the epicenter to the warning sign came with 10.5 seconds to advance. Further west and northwest margins improved slightly: 25, 30, up to 40 seconds before the devastating wave. Can not do better, with so violent an earthquake (magnitude 9), and so near the coast (130 km, where the tsunami reached speeds of a thousand miles an hour): paradoxically, the technology has worked well and their is little room for improvement .
But it is clear that with a notice so small the chance to save themselves are void. Outstretched so for the short-term forecasts. But it fared no better in Japan even for long-term, thanks to technology, early warning, many Japanese have received a message on the phone before the shock or probabilistic.
These studies are based on observation of the detailed movements of the faults and the use of statistics. The "Study Group on the probability of an earthquake in California" (Wgcep) which is headed by the University of Southern California, for example, has calculated that the region will be hit by an earthquake of magnitude 6.7 or greater over the next thirty years with a probability of 99%.
But this information has on the utility, when it is impossible to determine exactly where and when the earthquake hit. This time, however, also calculate the probability was disappointed seismologists. In the Tohoku region, the Big One hit from 11 March, an algorithm was applied to assess the risk of earthquakes with magnitude greater than eight.
This is done by computer processing on the basis of geological data taken on the ground, and in July of 2010 had included a high alert in the north-east of the archipelago. But a few months later, one of the parameters used was down to just below the threshold. Result: The alarm for the Tohoku region was canceled in January 2011, exactly two months before the earthquake.
These computer models in Japan (unlike California) are still used on an experimental basis and the cancellation of the alarm had no reflection on the practical emergency response. But do understand how much we are far from having available effective forecasting system for earthquakes. "The latest earthquake - confirmed Alex Martelli, seismic engineering at the University of Ferrara, director of the center of Eneas Bologna - have shown that the probabilistic analysis are still inadequate.
They have failed in New Zealand and China, to mention just the latest earthquakes . The algorithms that we tend to exclude rare events, but such cases happen sooner or later. We must improve our methods, and for this we need time. " Few improvements are expected instead to the 'early warning: the system worked as it should and would be difficult to ask more.
"The alarm uses the difference in speed between two types of seismic waves," says Charles Lai, head of the seismology all'Eucentre University of Pavia. "The P waves or longitudinal waves, traveling in the ground at a speed high: 2.5-3 kilometers per second. But they are the least harmful.
S waves are transverse or those really destructive, but spread at a rate about 1.7 times lower. When our instruments record the fast waves, so we have a small margin of time before they get those slow and devastating. In these few seconds we can take some emergency measures very quickly.
But it is impossible to do more. In Japan, these days, the system has also shown in defaillances accurately determine the epicenter of some of the aftershocks. "Yet none of the other countries that have the 'early warning (California, Mexico, Taiwan) has equipment up to those of Tokyo. 
TV and radio programs were interrupted to broadcast the alarm. The high-speed trains, obedient to the orders transmitted by computer, have slowed down and stopped to avoid derailment. Yet, incredibly, the network of 'early warning "were not linked to nuclear power plants. The implants are considered so important that it deserves a special network, which in fact was still being tested when the earthquake struck on Friday.
Not much better was the tsunami warning. On the beaches closest to the epicenter to the warning sign came with 10.5 seconds to advance. Further west and northwest margins improved slightly: 25, 30, up to 40 seconds before the devastating wave. Can not do better, with so violent an earthquake (magnitude 9), and so near the coast (130 km, where the tsunami reached speeds of a thousand miles an hour): paradoxically, the technology has worked well and their is little room for improvement .
But it is clear that with a notice so small the chance to save themselves are void. Outstretched so for the short-term forecasts. But it fared no better in Japan even for long-term, thanks to technology, early warning, many Japanese have received a message on the phone before the shock or probabilistic.
These studies are based on observation of the detailed movements of the faults and the use of statistics. The "Study Group on the probability of an earthquake in California" (Wgcep) which is headed by the University of Southern California, for example, has calculated that the region will be hit by an earthquake of magnitude 6.7 or greater over the next thirty years with a probability of 99%.
But this information has on the utility, when it is impossible to determine exactly where and when the earthquake hit. This time, however, also calculate the probability was disappointed seismologists. In the Tohoku region, the Big One hit from 11 March, an algorithm was applied to assess the risk of earthquakes with magnitude greater than eight.
This is done by computer processing on the basis of geological data taken on the ground, and in July of 2010 had included a high alert in the north-east of the archipelago. But a few months later, one of the parameters used was down to just below the threshold. Result: The alarm for the Tohoku region was canceled in January 2011, exactly two months before the earthquake.
These computer models in Japan (unlike California) are still used on an experimental basis and the cancellation of the alarm had no reflection on the practical emergency response. But do understand how much we are far from having available effective forecasting system for earthquakes. "The latest earthquake - confirmed Alex Martelli, seismic engineering at the University of Ferrara, director of the center of Eneas Bologna - have shown that the probabilistic analysis are still inadequate.
They have failed in New Zealand and China, to mention just the latest earthquakes . The algorithms that we tend to exclude rare events, but such cases happen sooner or later. We must improve our methods, and for this we need time. " Few improvements are expected instead to the 'early warning: the system worked as it should and would be difficult to ask more.
"The alarm uses the difference in speed between two types of seismic waves," says Charles Lai, head of the seismology all'Eucentre University of Pavia. "The P waves or longitudinal waves, traveling in the ground at a speed high: 2.5-3 kilometers per second. But they are the least harmful.
S waves are transverse or those really destructive, but spread at a rate about 1.7 times lower. When our instruments record the fast waves, so we have a small margin of time before they get those slow and devastating. In these few seconds we can take some emergency measures very quickly.
But it is impossible to do more. In Japan, these days, the system has also shown in defaillances accurately determine the epicenter of some of the aftershocks. "Yet none of the other countries that have the 'early warning (California, Mexico, Taiwan) has equipment up to those of Tokyo.
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