- Статьи
- Science and technology
- From the point of disaster: scientists have found a way to predict a tsunami in 2.5 days
From the point of disaster: scientists have found a way to predict a tsunami in 2.5 days
Russian scientists have proposed a new method for early tsunami warning. It is based on an analysis of changes in the Earth's magnetic field. The development makes it possible to predict catastrophic events approximately 2.5 days before they occur. The method was tested using the example of an earthquake off the coast of Fukushima in Japan, which caused a powerful tsunami. Later, it was confirmed by the material of smaller tectonic events. Including at the Simeiz–Katsiveli training ground in Crimea. However, more statistical data is needed to verify the method, experts say.
How electric currents predict earthquakes
Researchers from the Crimean Astronomical Observatory of the Russian Academy of Sciences have proposed a new method for predicting tsunamis — long waves that occur due to a sharp displacement of the water mass as a result of underwater earthquakes, volcanoes and landslides. The proposed method is based on an analysis of changes in the Earth's magnetic field.
Deputy Director of KRAO Alexander Volvach at the radio telescope control panel at the geodynamic range of the Crimean Astrophysical Observatory
As the scientists explained, the development allows predicting catastrophic events about 2.5 days before they occur. Such a forecast provides sufficient time to evacuate people in time and take measures to put hospitals, nuclear power plants and other vital facilities on high alert.
— Tectonic processes in the earth's crust can generate electromagnetic signals. For example, the rapid displacement of rock masses or their intense friction along a fault creates electric currents. They, in turn, form magnetic fields that overlap with the main field of the Earth," Alexander Volvach, head of the study and Deputy director for Scientific Work at the Crimean Astrophysical Observatory, told Izvestia.
Roughly speaking, the scientist explained, before the earthquake, the planet seemed to be preparing for it. So, a few days before the tremors occur in the zone of the future epicenter, giant blocks of the earth's crust shrink and crack.
During these processes, electric currents arise in the rocks. They form small magnetic fields. These changes are so small that they are difficult to detect with conventional instruments. Therefore, experts do not study the fluctuations themselves, but resort to collecting statistics.
The development was based on data obtained from the earthquake off the coast of Fukushima Prefecture in Japan, Alexander Volvach said. It occurred on March 16, 2022 and caused a powerful tsunami wave.
— Experts have analyzed the data from three magnetic stations, which are located at a distance of several hundred kilometers from each other. Based on the analysis, cases have been identified where 62-69 hours before the occurrence of tremors, instrument registration schedules are arranged in certain structures that can serve as harbingers of earthquakes. These data were confirmed by the material of smaller tectonic events," the specialist explained.
How to predict a tsunami
According to the scientist, subsequent studies have also suggested characteristic ensembles of precursors that are associated with the subsequent occurrence of a tsunami.
— It has been observed that for earthquakes that trigger tsunamis, the strongest signal goes along the vertical component of the planet's magnetic field. This is because such a component reacts to the movements of the earth's crust in the same direction. They are the ones who push the column of water up, creating a tsunami. This allows us not only to predict earthquakes, but to understand whether a giant ocean wave will follow it," said Alexander Volvach.
RT-22 radio telescope with a 22-meter mirror at the geodynamic range of the Crimean Astrophysical Observatory
In addition, such signals can be picked up by stations that are hundreds of kilometers away from the epicenter. This means that it is not necessary to build new sensor networks in seismically dangerous regions to predict tsunamis. It is enough to use the existing global network of magnetic observatories, the scientist added.
Currently, the Simeiz–Katsiveli geodynamic polygon has been created at the Crimean Astrophysical Observatory of the Russian Academy of Sciences to track such events. It is located on the southern coast of the Crimean Peninsula, near the village of Simeiz, 20 km west of the city of Yalta, the specialist said.
The scientific complex includes a 22-meter RT-22 radio telescope and two laser installations, as well as a magnetic variation station, which is responsible for recording magnetic variations, and a chemical station. The latter complex is designed to study the electrochemical processes that occur in the Earth's crust.
In addition, scientists have created a statistical apparatus that allows them to detect hidden patterns in the data series related to the occurrence of earthquakes and tsunamis.
The possibility of short-term forecasting
— The method is certainly promising. To implement it, we need a well-developed network of stations to monitor variations in the geomagnetic field as harbingers of seismic events. Currently, there are only five or six such stations in Russia. The proposed approach complements traditional methods of seismic and geodetic monitoring, creating opportunities for integrated forecasting," said Alexander Lukin, Executive Director of the West Caucasus Scientific Center.
Implementation may face insufficient funding. In addition, owners of sites with conditions that are clean from external geomagnetic influences often prevent the placement of equipment on them, because they do not see commercial benefits in this, he added.
— Modern forecasting methods work when the tsunami wave has already started. Scientists have models of the seabed relief, data on the rate of wave propagation, which depend on the depth. For example, in the open ocean it moves at a speed of about 720 km/h. At depths of more than 6 km — 800-900 km/h (like an airplane flight), — Sergey Mukhametov, senior lecturer at the Geography Faculty of Moscow State University, told Izvestia.
He explained that bottom pressure sensors and buoys anchored in the ocean are used to study tsunamis, as well as satellites with altimeters that measure the height of the ocean surface with high accuracy (about 2 cm) and can record the passage of waves. After recording a tsunami, experts can simulate where it will go, at what speed and what height it will reach off the coast.
There are developments to predict a tsunami in advance, the expert noted. For example, there are theories that relate to the trapping of precursor waves in the Earth's crust, the release of radon gas, changes in the ionosphere or the Earth's magnetic field before earthquakes. They often talk about the behavior of animals — fish, birds — that can feel faint vibrations of the earth that are not felt by humans, which can also be a sign. But so far, these are just hypotheses based on isolated cases. A reliable method requires a large statistical sample.
— As for long-term and medium-term earthquake forecasts, there is a certain consensus in the scientific community on the methods used for these purposes. In the field of short—term forecasts, there are many interesting and reasonable proposals, which, however, are mostly being worked out," said Sergey Pulinets, Doctor of Physico-Mathematical Sciences, Chief Researcher at the Space Research Institute of the Russian Academy of Sciences.
Tsunami predictions are a more complex issue than earthquake forecasting, he added. In addition to the tremors themselves, there are many other factors that determine the occurrence of a tsunami, the speed and direction of wave propagation. This includes rock features, bottom relief, underwater currents, and others. Therefore, the method proposed by the scientists requires detailed study in combination with these factors, the expert concluded.
Переведено сервисом «Яндекс Переводчик»
