The highest index of seismic risk in Russia, according to scientists, has the Krasnodar Territory. Such data for the people living in the Kuban are unpleasant. Indeed, about 28 districts of this region fall into the risk zone. About 4 million Kuban live in it (the total population is 5 million).
If we turn to history, then we can safely say that the earthquake in the Kuban is a fairly frequent phenomenon.
Since 1973, 130 tremors have been recorded here, the strength of which was 4 points or more. Earthquakes with an indicator of 7 points in the Kuban occurred approximately once every 11 years, and at 6 points repeated every 5 years. Each year, about 240-270 tremors with an amplitude of 3 points are recorded in the region.
When was the last significant earthquake recorded? 08/08/2016, as evidenced by official sources.
The reasons for the unfavorable seismic background in the Kuban
According to scientists, since 1980, any earthquake in Krasnodar is caused by the accumulation of excess voltage, which can provoke tremors. A confirmation of this hypothesis is the earthquake that occurred in 2014 in Karachay-Cherkessia and Dagestan.
Taking into account the statement of the researchers, the governor of the Kuban, Alexander Tkachev, issued an official resolution on increasing the level of stability of buildings in settlements in which seismic instability is noted. It was primarily about resort towns such as Anapa, Gelendzhik, Tuapse, Sochi, Novorossiysk. Among them was metropolitan Krasnodar. Here and earlier houses were built taking into account that they will withstand tremors of 3-4 points. Currently, there is the problem of strengthening buildings, which will require significant financial investments. It has already been decided that the state will allocate about 5 billion rubles for these purposes.
It should also be noted that if the worst assumptions of scientists are justified, then approximately 98% of buildings can suffer from earthquakes in the Kuban.
General earthquake data
Strong-magnitude earthquakes are classified as a disaster and, in terms of the number of dead, are replaced only by typhoons. The natural phenomenon in terms of destructiveness is several times ahead of volcanic eruptions. Material damage from one major cataclysm can amount to several hundred million dollars. Most often earthquakes of medium amplitude occur. According to researchers, of the hundreds of thousands of such natural phenomena, only a few have disastrous consequences. They contribute to the release of approximately 1020 J of potential seismic energy, which is equal to 0.01% of the thermal energy of the Earth radiated into space.
A bit of numbers and theory
Earthquake centers are located at a depth of 700 km, but most of the seismic energy is generated in the foci, which are at a depth of up to 70 km. The size of the focus of large earthquakes can be equal to 100x1000 km. Its location and the beginning of the movement of masses (hypocenter) will be determined by recording seismic waves that occur during tremors. In earthquakes of small amplitude, the focus and hypocenter coincide.
The epicenter is the projection of the hypocenter onto the surface. Around it lies the area in which major destruction occurs (epicentral or pleistoseist).
Earthquake intensity
The intensity of tremors on the earth's surface is measured by points and depends on the depth of the source and magnitude of the tremors, which serves as a measurement of the energy of an earthquake. The maximum magnitude is 9 points.
Magnitude depends on the total energy of the earthquake, but this relationship is not direct. It is logarithmic. With increasing magnitude per unit, the energy also increases 100 times.
How often does the Kuban shake?
Kuban is located in the zone of increased seismic activity. How often earthquakes occur in the Krasnodar Territory? The statistics of our days indicate that there are approximately 300 small tremors per year.
Residents complain that chandeliers are swinging in the house, dishes are ringing. But in the vast majority of cases, citizens are unaware of fluctuations. This is explained by the fact that the strength of the shocks is not so high, and they are recorded only by seismological instruments.
Seismic activity
The history of earthquakes in the Krasnodar Territory has many cases.
Facts have come down to us that describe the cataclysms that occurred in this area in the 4th century BC. e. The historian Flegont Traliysky in his essay “On the earthquakes of Theopom of Sinop” wrote about the tremors that occurred in Boyopor (today's Taman Peninsula). According to the author, during a sudden earthquake, one of the hills was cut in half, and huge bones erupted from it.
In 417 AD, Paul Orozil wrote in the Essay on General History that during this period Tsar Mithridates celebrated the festival of Ceres in Boepor. Suddenly, very strong tremors began. They contributed to the destruction of many cities and fields. Presumably, the magnitude of this earthquake was 7 points.
On the Taman Peninsula, a major eruption of the volcano Kukuoba, which was accompanied by an earthquake. This event occurred on March 10, 1793. A natural cataclysm caused the destruction of the tomb of the battle of King Satyr I.
The earthquake in the Krasnodar Territory was recorded by the catalog of the Russian Empire, containing all kinds of data about this cataclysm. At 19:00 in Yekaterinodar (Krasnodar), two powerful tremors were noted, which were noticeable throughout the Kuban region. This happened on September 19, 1799. A new island was formed on the Sea of Azov directly opposite Temryuk. Its appearance was facilitated by a large explosion that caused thick smoke and fire. The strength of the earthquake was 5 points.
Powerful shocks with an amplitude of 7 points shocked such cities as Yekaterinodar, Kizlyar and Mineralnye Vody. It happened on March 9, 1830 at 13:10. In the same year, on November 22 at 9:00 an earthquake was recorded with an amplitude of 8 points. Tremors were felt in places like Anapa and the Taman Peninsula. Fortifications were partially destroyed.
An earthquake in the Krasnodar Territory was recorded in February 1834. He was distinguished by a short duration. It lasted about 3 seconds. We recorded it in the region of Anapa and the Black Sea. Oscillations of the soil spread to the mouth of the Kuban River. The dilapidated buildings of the fortifications were put into disrepair. The tremors were preceded by a noise in the air, which came from the mountains in the direction from east to west and was reflected from the sea by a special hum.
As a result of an earthquake of strong amplitude, amounting to 7 points, in some old buildings of Anapa, the corners diverged and pipes fell from the stoves. It happened on December 26, 1842. The duration of tremors was 3 seconds. Fluctuations of the earth were felt in the Nikolaev and Vityazevskaya villages, the Dzhemeteysky fortification and Fort Raevsky.
Over the course of the 18th century, more than 20 shocks with an amplitude of 8 points were recorded in the region of the North Caucasus. On the territory of the Kuban, Anapa and Sochi belong to areas with increased seismic activity. Over the past two centuries, 10 earthquakes with a magnitude of 7 points were noted in these cities.
Anapa and Novorossiysk characterizes the concentration of fault crossing zones. They stretch along the coastline located in the Caucasus. Here is the western region of the meganticlinorium of the Greater Caucasus. It is divided into two parts - northern and western. The complexity and contrast of the geological situation provoke the occurrence of tremors of strong amplitude, greater than in other areas of the region located on the coast. A detailed study of the neotectonic situation in this area indicates that not so long ago there were destructive earthquakes with a strength of at least 9 points. For example, the Arkhipo-Osipov earthquake. His strength was 7 points. Major destruction in Novorossiysk was not noted.
The last earthquake in the Krasnodar Territory occurred in Novorossiysk on August 24, 1992. His strength was 5 points. In addition, on the territory of the city, scientists recognized the Pear beam and Abrau-Durso as the most active seismic points.
It should be noted that an earthquake in Krasnodar, whose strength would be 8 points, is rare. Although mountain formation processes are constantly taking place in this zone.
An earthquake of 3.5 points occurred in the Kuban on August 25, 2015. The epicenter was the sea. Since the beginning of October 2014, it has been shaking twice. No destruction was noted. Exactly one year later, on August 7, 2016, it repeated. And, fortunately, it was not destructive either.
The last earthquake that occurred in the Kuban
Was there an earthquake in the Kuban this year? 08/07/2016 - the date that was marked by tremors in the Yeysk region. Tremors were recorded at 11:15. The epicenter of the earthquake was Ukraine (Mariupol region). According to geological reports of the United States, the amplitude of the shock was 4.8 points. The oscillation of the earth was quite palpable. They were felt by the inhabitants of the Yeisk, Shcherbinovsky and Starominsky districts of the Krasnodar Territory, as well as the neighboring regions of the Rostov Region.
The representative of the seismological station Anapa said that the earthquake in Yeysk (Krasnodar Territory) spread the waves to the city of Abinsk. According to him, in addition to this impulse, weak fluctuations of up to 3 points were also recorded by the devices. Residents of cities such as Anapa, Krymsk, Gelendzhik and Novorossiysk also experienced an earthquake.
The natural disaster that took place on August 7, 2016, did not bring sacrifices and destruction. So reported Kuban State Television and Radio Broadcasting Company.
Can an earthquake be predicted?
People have long been thinking about the problem of predicting tremors. Interest in this matter is extremely high. After all, an accurate forecast will save many human lives. Due to the many unclear points associated with this natural disaster, it is extremely difficult to predict its onset.
Nevertheless, scientists from different countries do not give up hope to find methods that allow at least somehow to predict the process. The material obtained as a result of experiments is constantly collected and systematized. Work is carried out in laboratories and in nature.
What plays an important role in earthquake zones?
In areas with increased seismic hazard, a huge role is played by the construction of earthquake-resistant structures.
In Sochi, there are experimental buildings standing on movable supports. Even a strong wobble of the earth cannot destroy them.
The division of the territory according to the degree of potential threat is included in the functions of seismic zoning. It is based on historical data on earthquake recurrence, geological mapping, earth crust movements and instrumental observations. Zoning is related to earthquake insurance.
Seismic service
Earthquake observations are carried out by the seismic service. In the world there are more than 2000 stations, the indicators of which are constantly published in seismological observations, reports and catalogs. In addition to stations, expeditionary seismographs are used, which are installed deep in the oceans. Such devices were even sent to the moon, where every year five of them record up to 3,000 tremors on the surface of the planet. Also, devices were sent to Venus and Mars.
How does a seismic station work?
On a pedestal made of concrete, which goes deep into the earth by one and a half meters, there are special sensors that detect vibrations of the earth. They are converted into an electrical signal and recorded in a seismological station. These data go directly to the computer. Their analysis can only be done by a specialist. He can tell about the magnitude of the tremors and determine their epicenter.
Are there seismological stations in the Krasnodar Territory?
Such seismic stations exist. There are three of them. They are located in cities such as Sochi, Anapa and Krasnodar. These cities were not chosen by chance. So control of the territory is carried out in the center, as well as in the coastal area. The earthquake in the Kuban is most often recorded precisely in these areas.
Are weak earth vibrations dangerous?
Small amplitude earthquakes do not carry any danger. Moreover, they are useful, as they contribute to the removal of excessive tension in the earth. The accumulated energy is released in stages.
It should be noted that small-amplitude fluctuations, if they are repeated often over a short period of time, may indicate an impending major catastrophe. But, according to scientists, major disasters happen once every 500 years. The last time the most powerful earthquake in the Krasnodar Territory was recorded in the XIX century.