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A few seconds after the earthquake that devastated L'Aquila, in Abruzzo, a group of seismologists, south of Paris, already knew that a quake of earth had to produce. Their instruments? The Web. Seismologists? Witnesses themselves. To achieve this, a team that has worked for several years to develop a computer sophisticated. The project at CSEM, tells us.

Installed at his workstation, Nathalie Dupont taps on his keyboard. Suddenly, his chair began to move. The cup of coffee placed on the desktop flicker. A slight rumble was heard and a few cries resound. The leaves of the green plant agitated. Most people remain static, others are already crouched under the table while several came running to the stairs of service. But everything stops, and after a few seconds, everyone realizes that everything is finished and many understand that the shock is probably due to an earthquake.

Is this a local phenomenon, profound and serious? Or the earth she shook mightily to tens of kilometers away? Nathalie Dupont is already in the process of interviewing the Web. With the keywords "seismological center", it falls on the address of the Euro-Mediterranean Seismological Center, or CSEM, aka European-Mediterranean Seismological Center. Perhaps trouvera Does information?

Nathalie is not alone. The servers are already CESM of an exceptional peak of connection requests. Almost what feared an attack by pirates denial of service by saturation. This scenario is not fiction ...

"The average connection is about 150 per minute," says Rémy Bossu, head of the CSEM. At the time of the earthquake of L'Aquila, this number rose to 1,600. "Several years ago, this gave the idea analyze these requests. If it were possible to determine their geographical origin, with IP addresses, this sudden influx could be detected automatically and the earthquake zone would be identified.

Locate a pic abnormal connections

This idea has been implemented by several years of development. For it is precisely the role of CSEM to gather information from agencies responsible for monitoring earthquakes to locate as soon as possible a seismic event. The NGO coalition monitoring networks in 55 different countries in the region surrounding the Mediterranean. But on the Web, its audience is now well beyond. "Customers who visit our site come from 140 countries", says Rémy Bossu.

To achieve this seismometer of a new genre, it was necessary to build a technical tool to record the addresses IP and linked to a geographic area. CSEM turned to a British company, Digital Element. After the collection of raw data, analysis software must determine whether or not a pic and submit the information.

Since the first turns of wheels in 2004, the system has demonstrated its effectiveness. It is now able to detect and locate an earthquake after a period of, on average, between five and twelve minutes, a performance out of the reach of conventional tools of seismology. CSEM can quickly locate an earthquake, locate and even have an idea of the damage.

Over the years, the effectiveness of the system has even increased, because the analysis was refined, but also thanks to the witnesses themselves. "In Romania, north-east of Bucharest, were recorded in recent years an earthquake nearly a year, in the same place. In 2004, for the first event we have detected through the web, we took 8 minutes. But in 2005, five minutes were enough, then four minutes in 2006 and two minutes in 2008! "Why? Because the number of Internet access has increased and because many Romanians have used the address of the CSEM. Instead of searching the Web, they go there directly. This effect was seen also in Bulgaria, where a first quake had not resulted in an influx of calls, while the following was clearly detected. "The system learns by himself ..." says Rémy Bossu.

Because this is in seconds that there are soaring calls. "The proportion of access ADSL, so permanent, increased stresses Remy Bossu. The connection is faster." In 2004, connection requests were sampled every 20 seconds. But it took shorten this period to reflect the increase in the number of calls and the speed of Internet. Today, monitoring is carried out at 5 seconds and it will further reduce this period of sampling ...

There are also traps. Of course, the peaks are more intense if the earthquake occurs near a large city. The magnitude of the response of the Internet may even be greater after a mild earthquake and deep but the hypocenter is located in a sprawling city after a powerful earthquake in a sparsely populated region. This instrument does not measure the power but the amplitude geological felt that, indeed, any other measurement system does.

Television dilutes the information

Other effects may be more subtle. During the earthquake of L Aquila, CSEM screens have shown the affected area. But just days later, when a replica was made by a church collapsed in front of the television cameras that transmit live images, "it's all over Italy, which was lit on our screens." Similarly, in Turkey after an earthquake near Istanbul, the peak access was low, but on screen the whole country was ablaze on the screens some time later. The explanation was found: in one forum, someone had given the address of CSEM ...

With the rapid sampling, this kind of distorted data does not lead to an error. It is a local and early peak which is taken into account. Similarly, where a really serious earthquake caused widespread destruction, there is no witness on the spot to connect to the Web. In this case, the lack of local connections, a fall rather than a peak, so that the signal is enhanced by an increase in requests from regions close to the epicenter.

Information, too, can happen very quickly. In February 2007, a strong earthquake was felt on the coasts of Morocco and Portugal. In the beginning, we knew the severity of the damage. The French authorities immediately contacted the CSEM who gave his reply without delay: to Lisbon and the coast, the number of connections was very high, so the Portuguese capital and its region were good.

Within minutes after the earthquake, the severity of damage can be estimated by other means, much more precise. Visitors become witnesses are asked to complete a questionnaire on what they saw, felt or heard. It is now possible to do even better. Rémy Bossu as shown in the video, the owners of mobile phones equipped with cameras are becoming as assistants seismologists. They can send images of phenomena that a geologist had little chance to observe a day as this cloud of dust on a mountain in Chile, caused by landslides after the earthquake.

The value of the system goes beyond the alert and therefore also interested in the scientific community. Eventually, seismologists will have a direct access to these data, those that come from the Internet.