The earthquake in Turkey has been called the disaster of the century. The tremors, the magnitude of which reached 7.7 points, caused enormous damage, claimed the lives of 49,000 people and more than 115,000 were injured. The situation has caused particular concern among residents of the Black Sea coast of the Caucasus, reports that underground rumors have been recorded in the Sochi region from time to time appear in news feeds. How earthquakes are monitored at the station, whether they can be predicted and the durability of high-rise buildings in Sochi, our correspondent understood.
The station has a special seismic station
Everyone remembers from school geography lesson that the surface of the Earth, or rather the lithosphere, is made up of plates that are constantly moving and colliding. Where the plates collide or move away from each other are seismic belts – places with the greatest activity. One of these belts, the Pacific Ring of Fire, runs around the perimeter of much of the ocean territory in Asia and North America. Another important seismic zone is the Mediterranean-Himalayan belt. It crosses Europe, Africa, India and Southeast Asia with a total length estimated at more than seventeen thousand kilometers. And there are two news – good and bad. The Caucasus Mountains are in an area where the magnitude of an earthquake can reach eight points. At the same time, the Mediterranean-Himalayan belt accounts for only fifteen percent of global earthquakes. And the probability of eight-point tremors – once every five hundred years. By the way, for the past hundred years there have been no such places in the vicinity of Sochi. A special seismic station monitors this at the station.
- There is a fixed seismic station in Sochi, as well as temporary stations in Krasnaya Polyana, Veseloe and Lazarevsky. There are seismic stations in Agoy and Guzeripl. The seismic stations are equipped with instruments located in the underground pavilion, they are deepened on the base, connected to the bedrock in order to record any vibration. If we take our station, we record the earthquakes that occur all over the world. An earthquake is a waveform. This can be visualized on the water when you throw a stone, and circles come out of it in different directions. Waves also come from earthquakes. Depending on the strength of the earthquake, echoes occur at such a distance, ”says Elena Karpovich, head of the Sochi seismic station.
In the entire history of observations, and it is already more than a hundred years old, the strongest earthquakes in the Sochi region were recorded seven times, the strength of shocks ranged from five to seven points. Fortunately, there were no casualties. The most active earthquake of 1955 in the Krasnaya Polyana region caused damage to the hydroelectric power station. Many residents of Sochi remember the last strong tremors, in 2012 their amplitude was 5.7 points, chandeliers swayed among the inhabitants of the upper floors of buildings, “curved” windows.
— For the most part, earthquakes around three points are recorded in our region, they are practically not felt, many do not even realize that they live in an area with increased seismicity. At the same time, such earthquakes can be called a kind of energy discharge that accumulates during the movement of tectonic plates. They allow it to go out, do not allow it to accumulate, which can lead to large-scale tragedies, says Elena Karpovich.
What is important to know
Despite active work, scientists cannot yet predict when and where an earthquake will occur. But the most important thing in this case is not to panic. Being on the street, it is worth getting away from buildings and being inside the house, remember that the interior walls are always stronger than the exterior ones.
And the tsunami? Such waves can occur in absolute calm due to sea shaking. Recently, a new set of rules for tsunami-prone areas was published in Russia. If earlier it included such places as the Kuril Islands, Southern Kamchatka, Sakhalin, where the wave can reach two or three meters and have destructive power, then this time the Black Sea also entered it.
- According to the new set of rules, the Black Sea in the Anapa region and the Lazarevsky district of Sochi also entered the tsunami zones. The estimated wave height once in a thousand years here can reach half a meter along the way. At the same time, a tsunami up to a meter high poses a low danger. But if such a wave penetrates from the sea into a narrow structure, then it can concentrate. This must be taken into account when creating marinas and other structures. The whole fight against the tsunami comes down to the fact that the bank protection fortifications must be of high quality and people must go to a hill,” said Konstantin Makarov, a professor at Sochi State University.
Of course, man still has no control over an earthquake or a tsunami. But still, there are ways to try and ensure your own safety. The most important of these is good construction. Turkey’s sad experience has shown that great destruction could have been avoided if building codes and regulations had not been violated. By the way, it was also the main cause of destruction during the strongest earthquake in the Caucasus, in the Armenian city of Spitak. After him, a sad anecdote even appeared among architects and builders.
Who is responsible for the collapse of the building? Armature?
“No, that’s fine, that’s enough.
- Bricks ?
We are all strong.
- Cement?
- What do I have to do with this? I wasn’t there at all…
It would be funny if it weren’t so sad.
Safe Sochi
As for Sochi, its construction history can be conditionally divided into several periods. The first is Soviet. At this point, a number of design and research institutes were responsible for building the city.
— Complete studies, design and field supervision during the construction process have been carried out. With the responsibility resting with the institutions, the city received complex development projects with a perfect understanding of the adequacy of the territories: where it is possible to build, and where the land can only be used for agriculture. The cartographic and scientific base has been constantly updated. To obtain the building permits, it was necessary to set up and coordinate the project. Architects, designers and surveyors worked on the project, calculations were made, models were prepared. In Soviet times, institutes made developments, survey materials, monitored landslide processes, the coastline, carried out technical monitoring of water bodies, literally people walked through forests, along rivers , described all possible processes, marked them on maps, everything was entered into a single database. This knowledge base of seismic processes, landslide processes, which was constantly replenished, and the archive could be used, – explains the chief geologist of the company Sochitisizproekt, Natalia Kichatova.
At the same time, the standard designs of Soviet high-rise buildings were improved taking into account seismic safety requirements. The buildings of this period, which were built in Sochi and its surroundings, were designed for earthquakes with a magnitude of eight points. The lifespan of the houses has been set at eighty years. Considering that the massive construction of the station took place in the 70s and 80s of the last century, it seems that there is no need to worry.
- In Sochi, there are quite often three-point tremors, which people may simply not notice, but they affect the durability of structures. One of the important steps in ensuring the seismic safety of the city today should be the inspection of Soviet-era buildings that have existed for more than thirty years to determine whether they require reinforcement or renovation,” explained Olga Shebzukhova, director general of the New Horizons Recreational Territory Development Center.
Another expert advice. Are you looking for accommodation in Sochi? Take care that the attics of Soviet high-rise buildings are not converted into residential attics or first floors, which were previously intended for shelters. All this affects the stability of structures.
Sochi’s engineering and architectural community is very concerned about so-called infill development. In recent years, such buildings have been erected with all sorts of violations of norms and rules, created on individual housing construction sites, for which soil surveys were carried out that were absolutely unsuitable for apartment buildings. Such houses, and their number in Sochi today is thirty percent of the total, can repeat the fate of Turkey.
— The safety of such buildings depends on a combination of factors: seismic activity, quality of design and construction. If the city does not take measures to regulate the process of exploration and construction, then in the next ten to fifteen years we will begin to receive the destruction of these new buildings, geologist Natalya Kichatova is sure.
The problem of modern construction in Sochi is not only the loss of archives and information, which in Soviet times were collected by more than three thousand engineers, urban planners, architects and other specialists of design institutes and of state surveying, but also the loss of the personal themselves. The same local specialists who knew and understood both the soils, the complex geology and possible dangerous earth processes on the territory of the station. Unfortunately, many large developers who came to the city have experience only in the creation of buildings in central Russia, which does not apply to mountainous areas. This is why it is necessary to solve the seismic safety problems of the station in a comprehensive way. One of the important steps is the revival of design institutes that existed in Soviet times to conduct long-term and permanent engineering studies, the formation of a database that will be used for the integrated development of the territory . Of course, it’s not a quick thing. But the first step has already been taken. Sochi has launched an engineering council, a public organization that brings together experts with experience in construction in seismic risk areas.
