An earthquake warning device was introduced by Akis Tselentis


Even a few seconds before a major earthquake came we knew it would surely save hundreds or even thousands of people.

Such an innovative system, which has been successfully tested in foreign countries such as Japan and America, now finds its way to Greece thanks to the program scientist and head of the Geodetic Institute, seismologist, Akis Zelentis.

ARIS, so-called the pioneering program, was recently presented by Akis Tselentis during the Thessaloniki International Exhibition, sparking enthusiastic comments.

Although initially aimed at protecting large industrial units, the system is easily expandable to protect wider urban areas. In summary, the system detects the occurrence of an earthquake, estimates its magnitude and its location, calculates the time they will reach an area, based on the distance from the center, the most dangerous from the seismic waves, estimates their effect. and informs of the upcoming disaster. With the alert time varying and estimated based on Greek data usually from 8 to 20 seconds, but even more so for distant earthquakes, the response margin is a life saver, which would otherwise be at risk.

In those few seconds, citizens can be covered, auto-activated protection systems, power or gas switches shut down, large companies cut off supplies of flammable materials, trains stop and avoid the worst.

“ARIS”, as the well-known seismologist explains, can be extended to Patras and the wider region of Western Greece also due to the strong seismicity of the area and due to the impending arrival of natural gas to protect its installations (already applied at the installations). of MOTOPOIL, in Corinth). Provided that the Region of Western Greece and the Municipality of Patras agree to promote the program.

Rescue notice

Valuable experience from the outside shows that the system not only works successfully, but also proves to be a lifesaver. On September 7, 2017, 32 years after the earthquake that struck Mexico, residents’ mobiles rang to warn people that Enceladus would be hit in a matter of seconds, while the alarm signal reached all of its critical infrastructures, and other sensitive structures, power plants, and Authorities, giving them the time needed to safeguard and take immediate action. Thanks to this warning thousands of lives were saved as they had time to act.

The research – pilot project – is currently running in the context of the ARIS program, focusing on the area of ​​the Eastern Corinthian Gulf, which is distinguished for its extremely high seismicity. For its implementation, specially designed sensors were developed, with the aim of densely covering the area. The software is based on state-of-the-art algorithms developed within the University of California, Berkeley, which “signs” the system that covers the west coast of the United States. “The help we had from the University of Berkeley was significant,” said Mr. Karastathis. At the same time, he explained that new algorithms are being developed by adapting them to the seismotectonic regime of the region, but also to investigate the effect of local soil conditions on the formation of the final seismic intensity. The ultimate goal of the program is the implementation of an Integrated Seismic Alert and Hazard Management System, tailor-made for industrial infrastructure, with pilot application at the facilities of the MotorOil Hellas refinery at Agioi Theodoroi.

How the system works

The original pilot earthquake early warning system, named ARIS, follows the basic principles of systems already operating in several countries successfully. The basic principle of its operation is simple: When an earthquake hits, the first wave to leave the hearth is the so-called P wave, known as the first or longitudinal wave, which runs at a speed similar to that of sound in solids around at 6 kilometers per second. These are followed by seismic waves S, known as second or transverse, which travel more slowly, at speeds of less than 4 kilometers per hour, but are the most devastating. This is exactly what they are trying to do and succeed in preventing the system by alerting the public to their arrival.

And how is this done? High-speed, ultra-modern seismographs detect the first weak P waves of seismic vibration. Special algorithms are used to estimate the magnitude and magnitude of the earthquake in a matter of seconds, and then calculate the time and intensity that are expected to cause the arrival of destructive S waves in an area. The system then undertakes to transmit the information to the area immediately so that there is as much reaction time as possible for the time remaining until the arrival of the waves. This time depends on the distance of the area to the focus, and there is the potential, as California’s original ShakeAlert system has been running since 2018, rapid revision to improve the identification of earthquake data during the process. For Greek data this time is usually between 8 and 20 seconds from the time the P waves start until the arrival of S. This is not a system of earthquake prediction, because the earthquake is precisely warned.

Battle over time

The big bet for scientists is to win the battle of time in the speed of transmission of signals to the central system, as it must almost be reset. It then needs to be connected to a range of automated receivers such as mobile or general information dissemination units, so that it can be practically usable, immediately informing large plant units, hospitals, other sensitive structures and Principles of the time of the catastrophic mania of Enceladus. And of course, before the final stage, a period of rigorous verification and modifications must have been completed in order to achieve 100% system reliability. This is in order for the information to be valid and to avoid false alarms and unnecessary messages.

The Greek system leverages the know-how developed at Berkeley University in California, which fortifies the west coast of the United States from Enceladus, focusing initially on vital infrastructures such as power plants, and then on alerting citizens earthquake area, who will receive a message on their mobile phone.

As tempo24 reports The system is under the auspices of the well-known US Geological Survey (USGS), with an average alert time of 10 seconds and is expected to extend to cover all the area in the “red” due to the dangerous fault. of St. Andrew.

The system, based on the speed of seismic wave propagation, will be located in areas of high seismicity, including Patras, while information on the upcoming earthquake will be initially “distributed” to factories and schools in the next phase. in hospitals and especially in surgeries, which is already under discussion, as well as with the Athens and Thessaloniki subways that fall into the category of sensitive structures during an earthquake. As for the time of warning, Mr. Zellentis said it depends on the distance the residential area is from the center – the farther away the more.

“SMS to citizens”

According to the Director of Geodesic, there are already thoughts with Civil Protection about the transmission of the mobile signal, but not currently to the public, as, according to Mr. Zellentis, there is still no maturity for a proper response. world because there is a danger of panic, which must be eliminated.

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