Seismologists predict earthquakes in Istanbul: ‘It was a rehearsal’

The earthquake that occurred on February 6 in the south-east of Turkey, some Turkish experts call a rehearsal of a possible Istanbul earthquake. According to scientists, unlike shells, a large earthquake usually “falls in one funnel,” so society must know and prepare for new shocks in advance. What does science say about the likelihood of continued shocks along the lithospheric plates? Where could something like the Turkish earthquake happen in the next 10 years? We talked about this with Yury Vinogradov, director of the Geophysical Service of the Russian Academy of Sciences.

To begin with, we recall that the terrible aftershocks of magnitude 7.7 with the epicenter in the Turkish city of Pazardzhik and 7.6 points in Elbistan in the province of Kahramanmarash led to 37,000 deaths and more than 100,000 injured residents.

The cause of the disaster was the displacement of the Anatolian tectonic plate in a southwesterly direction relative to the Arabian, by 3.5 meters in the area of ​​the epicenter of the earthquake. On the surface, it resulted in a gigantic soil fault in the province of Hatay, 150-200 kilometers long, 30 meters deep, and about 200 meters wide.

Where will the earth crack “go” next? Someone like the seismologists referred to by the Turkish publication Hurriyet, now they predict an earthquake in Turkish Istanbul, and such that what happened on February 6 will seem like just a rehearsal. What do they explain? The location of the city at the junction of the Anatolian and Eurasian tectonic plates and the fact that at a distance of 15–20 km from the city there is a section of the North Anatolian fault, passing under the Sea of ​​Marmara. “We are waiting for an earthquake with a magnitude of more than 7 in Istanbul at any moment,” the publication emphasizes.

Another specialist, the Dutchman Frank Hugerbits, from the scientific organization SSGEOS – the Research Institute for Tracking the Geometry of the Interaction of Celestial Bodies and its Influence on Seismic Activity – believes that after Turkey, one of the three countries should be pretty shaken up: Lebanon, Syria or Jordan. And already this year! Hugerbits is credited after he predicted a Turkish earthquake a few days before the deadly aftershocks.

Are there not many terrible predictions for one year? What do Russian scientists say about the possible consequences of the Turkish seismic disaster?

– I don’t know what the “stars” said to the Dutch specialist (in our country, such forecasts are also quite often issued by some experts, and sometimes they are successful), – says Yuri Vinogradov, – but, as for classical seismology, I tell you with full confidence: no one in the world can predict the underground processes leading to an earthquake in a week or even a month. There are too many uncertainties to create an adequate mathematical model. If we were dealing with homogeneous rocks, smooth fault boundaries that always move at the same speed, then we could give a “task” to a supercomputer, and it would calculate the date of the next earthquake. But the fact of the matter is that lithospheric plates always move at different speeds and directions, they are always affected by unpredictable atmospheric pressure, convective flows from the magmatic core, they have uneven boundaries, an internal structure that is heterogeneous and dissected by numerous faults, finally!

Can atmospheric pressure affect an earthquake?

– Certainly. It has long been noted that cyclonic activity affects the earth’s crust, and earthquakes often occur in cyclone zones. Hence the frequent mention of thunderstorms, clouds during or before earthquakes. That is, a change in atmospheric pressure can be a trigger for an earthquake. It’s like with a string on a guitar – just touch it and it will break! True, there is also a hypothesis that the source of the emerging earthquake, as it were, “attracts” cyclones to itself, due to gases released from the ground. Therefore, a certain type of cyclones can be one of the harbingers of an earthquake.

– The version that the displacement of the Anatolian and Arabian plates relative to each other can continue, at least theoretically, can it be confirmed? Someone compares the process of formation of a fault in the earth’s crust with a creeping crack on the windshield of a car…

– Not certainly in that way. Firstly, the displacement of the plates occurs constantly, which is why stress accumulates at their boundaries. Where this stress exceeds the strength of the host rocks, an earthquake occurs, which releases the accumulated stress, and a fault is formed. After the process of accumulation of energy begins again. Therefore, earthquakes are repeated after a fairly periodic period of time. But unlike glass, the earth’s crust is plastic, it is not so brittle, so a crack (a break in the earth’s crust) has a finite length. In the case of the Turkish earthquake – about 250 km.

– How do you feel about the forecasts of some Turkish experts about a possible strong earthquake in Istanbul due to a fault in the Sea of ​​Marmara?

– In August 1999, there was a strong earthquake near Istanbul with the destruction of houses and the death of people. In accordance with the statistics of the frequency of strong seismic events, the probability that a new earthquake is about to occur in the same place is very small. It usually takes 30 to 300 years for a new earthquake to accumulate energy in the earth’s crust. Everything is determined by the speed of movement of the plates relative to each other. Of course, there are exceptions, but not for such strong earthquakes.

– In our country, just following the logic of the average hundred-year interval between major earthquakes, many are “awaiting” a cataclysm in the Crimea, where the last strong earthquake was in 1927…

– Indeed, there was a strong earthquake in Crimea, but with a much smaller magnitude than in Turkey. The tectonics there is completely different. Crimea, although located on the edge of a tectonic plate, is still not on the very border.

– Where then is a really strong earthquake expected, in your opinion?

– Our service does not deal with forecasts for the population. If we have information about an upcoming earthquake, we share it only with the Ministry of Emergency Situations, and then their job is to warn. On the territory of our country, places are known where earthquakes periodically occur: these are Kamchatka, the Sakhalin region, Altai, the Sayans, the Caucasus. However, as I have already said, there can be no short-term forecasts for them. As for European countries, the most “hot” places in terms of subduction are Greece, Romania and the island of Crete.

Read also: “Turks furious after earthquake: developers punished, officials flee”