How to predict an earthquake. Radon release and animal behavior are warning signs of upcoming tremors

In the last days of June 1981, the capital of Peru, the golden-columned Lima, was in turmoil: American scientist Brian Bradley predicted that on Sunday, June 28, the city would be destroyed by an earthquake of extraordinary strength. Dozens of powerful tremors will turn crowded city blocks into dust, after which tsunami waves will fall on the smoking ruins, sweeping away with a terrible onslaught everything that, by some miracle, manages to survive. The coastal areas of the city around Callao Bay will fall below the ocean level and become the seabed. Blooming “sun-faced” Lima will disappear from the face of the Earth in a few moments.

As the “day of judgment” approached, the situation in the capital became tense. Thousands of distraught people stormed airports, train stations and ship piers, trying to leave the city condemned to death. Lines of cars, carts, pack mules and pedestrians with handcarts and knapsacks on their backs clogged the highways and country roads from the doomed city in search of salvation. Prices for gasoline and food soared, crime increased alarmingly, houses and land were urgently sold for next to nothing, hospitals were suffocating from the influx of people crippled in the growing panic.

But the hour indicated by the soothsayer approached, passed... and nothing happened. Torn to pieces, but unharmed and still beautiful, Lima continued to serenely bathe in the rays of the tropical sun. Nothing happened the next day or in the next few days. Gradually, the wounds inflicted on the city by the panicked flight of the population healed, the incident began to be forgotten and turned into a historical anecdote. The unlucky predictor of the failed catastrophe was recognized as a false scientist and declared a charlatan.

Well, it’s easy to understand the impressionable residents of the Peruvian capital, who chose to flee the city over certain death under the ruins of their houses. Their country is located in a very seismically dangerous area of ​​the globe. Over the five centuries that have passed since the discovery of the New World, 35 destructive earthquakes have occurred in Peru, and scientific observations over the past 100 years have recorded several thousand tremors of varying strength. There are probably few families in the country who do not mourn their loved ones who lost their lives in seismic disasters. The beautiful Lima also suffered repeatedly from strong earthquakes; in other tragic years, the underground elements destroyed most of the city.

Thus, the panic alarm of the residents of Lima had the most serious reasons. But back to the ill-fated Brian Bradley. On what and on what grounds he based his assumptions is still unknown. Therefore, it is not right now to condemn him in absentia, call him a pseudoscientist and accuse him of quackery, as the temperamental Latin American newspapers did. It is better to first try to understand the essence of the question: is it possible to predict the onset of earthquakes using the methods of modern science, that is, determine the place where they will occur, their intensity and time? After all, such forecasts (if they are issued in advance), like weather forecasts, will allow the population of threatened areas to prepare for expected natural disasters, take preventive measures and, if not prevent, then at least significantly reduce heavy losses and losses.

The possibility of seismic forecasting was suggested by the experience of observing natural phenomena, which, preceding seismic shocks, serve as harbingers of approaching catastrophes. It has long been noted that before some earthquakes, a weak diffuse glow spreads over the ground; sometimes it is accompanied by flashing flashes or similar lightning, reflections on the clouds (this happened in 1966 in Tashkent). In other places, a foggy haze appears, which spreads over the surface of the earth and disappears after shaking. It happens that before the tremors, a light rising breeze flows from the ground (in Japan it is called “chiki”) or a muffled underground rumble is heard; in this case, random oscillations of the magnetic needle occur and the lifting force of the permanent magnets changes.

All these physical processes that precede seismic vibrations influence the behavior of animals, allowing them to anticipate impending misfortune. Chronicles, historical documents and oral traditions of the peoples of Asia, America and Southern Europe tell about this. In the palaces of Chinese emperors, special freshwater fish were kept in special aquariums, which, with their restlessness, warned of the approach of a natural disaster. Before the earthquake, the population of Japan observed the sudden appearance of large schools of eels, tuna and salmon in the sea, unknown deep-sea species floated to the surface, and the usual widespread species suddenly disappeared. Many octopuses swam to the shores, usually nesting in the crevices of underwater rocks.

Frogs, snakes, worms and centipedes crawl out of their shelters before an earthquake. Rats leave their holes in advance. Birds fly towards quieter areas inland. Horses, donkeys, sheep and pigs show increased nervousness. Cats and dogs have a special premonition; There are known cases when dogs forced their owners to leave buildings that were subsequently destroyed by underground shocks.

There are also people endowed with the ability to anticipate seismic vibrations; Most often these are neurotic patients with increased mental excitability, but there are also healthy people who are characterized by heightened susceptibility. For example, in 1855, a servant of a Japanese samurai predicted a strong earthquake in the city of Iedo (the ancient name of Tokyo).

Based on all these observations, scientists came up with the idea of ​​​​the possibility of scientific prediction of earthquakes. This idea arose in the 50s of our century almost simultaneously in different countries that were subjected to the crushing onslaught of seismic disasters. To implement it, it was necessary to learn to use instruments to detect physical harbingers of tremors and use the data obtained for forecasting.

By this time, it had already been clearly established that earthquakes occur during rapid movements of blocks of the earth’s crust along the faults separating these blocks. It would seem that it is worth making observations of the behavior of geological faults - and the forecast problem will be solved: an increase in the activity of the fault will indicate the approaching threat of seismic tremors.

For this purpose, systematic instrumental observations were organized on many seismically active faults that experienced destructive earthquakes. It was expected that before the seismic tremors there would be an increase in the deformation of the tensile layers of rocks, the rise and fall of the contacting blocks of the earth's crust, sharp changes in the inclination of the layers (the so-called "tilt storms"), weak small tremors preceding the main shock ("microearthquakes") caused by the piezoelectric effect is an increase in the strength of telluric currents emanating from the seismic source, anomalous changes in the geomagnetic field (“local magnetic storms”) and a number of other phenomena that foreshadow the release of tectonic stress in the depths.

In fact, the situation was much more complicated. Indeed, in many cases the expected phenomena were observed; but often they contradicted the theoretical model of the process or revealed a completely unexpected, inexplicable course. Thus, in earthquake-prone areas of Alaska, a very slow (several centimeters per year) subsidence of the earth’s surface usually occurred. Three times - in 1923, 1924 and 1952 - abrupt “dips” were observed, during which the dives accelerated 5-6 times; however, no seismic phenomena were observed.

The destructive Anchorage earthquake in Alaska occurred in 1964 without any prerequisites in the form of a sharp subsidence or rise of layers. In the Japanese province of Niigata, where, on the contrary, gradual soil uplift prevailed, in 1959 the rate of uplift suddenly increased 10 times. A strong earthquake did not follow this jump, but broke out without visible precursors only five years later. The same inconsistencies were noted in the observed changes in the inclination of layers, the behavior of geomagnetic and electric fields, etc., although in some cases seismic tremors, as theoretically expected, were preceded by sharp outbreaks of anomalies.

Over three decades of research and search, it has not been possible to identify indisputable patterns that can be relied upon when predicting seismic shocks. Therefore, now none of the experts dares to assert that certain phenomena in the earth’s crust can be regarded as unambiguous harbingers of earthquakes and provide reliable grounds for predictions.

Currently, the circle of scientists working on the problem of earthquake forecasting is divided into two camps - skeptics and optimists. Skeptics believe that given the current state of our knowledge, which is completely insufficient, this problem is insoluble. At one time, the President of the USSR Academy of Sciences M.V. Keldysh called it fantastic. The most prominent American seismologist, Charles Richter, writes: “This is a tempting will-o’-the-wisp... At present, no one can say with certainty that an earthquake will occur at a given time in a given place. It is unknown whether such a prediction will be possible in the future.” The famous Soviet researcher of seismicity in Eastern Siberia V.P. Solonenko ironically cites a saying attributed to the Chinese sage Confucius: “It is difficult to catch a black cat in the dark, especially if it is not there.”

Optimists both in our country and abroad believe that the science of earthquake forecasting is on the right track and is already making significant progress. As a reliable precursor of tremors, they cite, for example, the flow of helium, argon, radon, chlorine, fluorine and other elements originating from the deep zones of the Earth into groundwater before seismic shocks, identified by Soviet scientists in some regions of the Caucasus and Central Asia; They also pin their hopes on studying the processes of dilatancy, the development of which also precedes the discharge of seismic elements. However, it has not yet been clarified how universal these phenomena are for territories with different geological structures. Some experts attach great importance to determining the periodicity of seismic processes. Thus, Japanese scientists, who have established a period of seismic activity of 69 years for the Tokyo area, are anxiously awaiting 1992, when, in their opinion, a “great catastrophe” similar to the earthquake with a magnitude of 8.2 that devastated the capital of the Land of the Rising in 1923 could happen again. sun. But recurrence phenomena are still very poorly studied, since systematic observations of earthquakes in the earth’s crust have been carried out for only about 100 years.

Under these conditions, it is clear what risks earthquake forecasters are exposed to and what responsibility they take on. There's nothing surprising about Brian Bradley's prediction, unless of course he is. was made on the basis of genuine scientific data, but was not confirmed. On the contrary, it would be surprising if everything that was predicted happened.

However, there are examples of successful forecasts. The first such forecast was made on February 4, 1975 in the Chinese province of Liaoning. By order of the authorities, the population of the cities of Haichen and Yingkou left their homes on this day, and measures were taken to prevent the destruction of factories, food warehouses, children's institutions and hospitals. At 19:36 a strong earthquake occurred (with a magnitude of 7.3), which destroyed almost all residential premises, many factories, dams and other engineering and industrial structures. Thanks to the security measures taken, there were very few casualties. After this, two more small earthquakes were predicted. However, Chinese scientists failed to foresee the tragic Tien Shan disaster on July 27, 1976, in which 680 thousand were killed and over 700 thousand were injured, and the total number of victims exceeded 1.4 million people.

Our country has experience in predicting one of the minor (5 magnitude) tremors in the Tashkent region, a small earthquake in the uninhabited area of ​​the Alai Valley near Andijan, and several other similar seismic phenomena in other areas of Central Asia.

It must be said that in all the examples given there is no guarantee that the accuracy of the prediction is due to the accuracy of the forecast, and not to a random coincidence. There are a number of counter-examples where predictions of supposedly future earthquakes have not been confirmed.

From time to time, mass sources of information suddenly begin to beat the timpani and widely announce extraordinary successes in the field of seismic forecasting, and it seems as if most of the problems of this important scientific area have already been solved. However, in fact, the situation is not at all so encouraging and the false pathos of this information remains on the conscience of its authors and distributors.

Indeed, except for a single case in Liaoning Province (Haicheng), during the 30-year period of work on the problem of seismic forecasting, not a single catastrophic earthquake was predicted in any region of the globe. In particular, as the famous Soviet researcher B.A. Petrushevsky points out, in the USSR no warning forecasts were made either for the Tashkent region in 1966, or for the Gazli region in 1976 and 1984, which is why the destruction there was so unexpected and severe. On the one hand, modern forecasting cannot yet identify the main harbingers of the upcoming release of seismic stresses and determine the location of the earthquake: during the dramatic catastrophe in the Chinese Tien Shan in 1976, observations delineated a vast seismic zone, but they could not determine the source of the seismic release; In this respect, the forecast of volcanic eruptions is in a better position because it deals with specific points on the ground.

On the other hand, the lack of ability to recognize and control the “trigger mechanism” of earthquakes does not allow us to determine the exact time of the event: after the 1964 Anchorage earthquake, many scientists came to the conclusion that it was provoked by a high sea tide, which acted as a “trigger mechanism” , increasing the load on the earth's crust. Before the earthquake this was not clear to anyone; at the same time, according to other experts, the initiator of the shock was a strong disturbance of the magnetic field, recorded 1 hour before the disaster. In addition, scientists do not yet have any direct methods for calculating the strength of possible vibrations.

Apparently, the most fair assessment of the problem of predicting earthquakes was made by C. Richter, who believes that at the current level of science, predicting the discharge of seismic energy is possible - without an exact date - only on certain tectonic faults that have been studied systematically and for a long time. It is likely that in the future, with the improvement of space survey methods and the deployment of a network of stationary ground observations, it will be possible to predict seismic phenomena over vast regions of the earth's surface.

It should be noted that seismic forecasting, while helping to solve the problem of reducing the number of human casualties, does nothing to prevent material losses and destruction during earthquakes. Therefore, work to clarify seismic zoning with differentiation of the territory according to the degree of danger, the development of earthquake-resistant construction in hazardous areas and the reduction of economic activity in highly hazardous areas are of much greater importance; these activities are aimed at solving both problems. Without setting themselves the goal of knowing exactly when an earthquake will occur, they allow themselves to be prepared for it at any time.

Recently, ideas have been expressed in engineering seismology about the possibility of controlling earthquakes. It has been noticed that underground nuclear explosions cause a series of subsequent, weaker earthquakes; similar phenomena occur after water is pumped into the subsoil through deep wells under high pressure. It is assumed that with such technical means it is possible to release energy accumulated in the depths and discharge it in small portions, preventing destructive tremors. Sensible experts note: there is no guarantee that the process will develop the way we want.

On July 23, the fourth earthquake in a day occurred in Iran, and the number of victims reached 287. A day earlier, tremors with a magnitude of 5.2 were recorded in Chile. In general, over 7 months of 2018, 6881 earthquakes occurred on Earth, taking 227 human lives. But why have scientists never learned to predict these cataclysms? Realist figured it out.

How are seismic zones determined?

Lithospheric plates are in constant motion. Colliding and stretching, they increase stress in the rocks, which leads to their rapid rupture - an earthquake. The source (hypocenter) of an earthquake is located in the bowels of the earth, and the epicenter is its projection on the surface.

The strength of earthquakes is measured on a scale of destruction in points (from 1 to 12), as well as magnitude - a dimensionless quantity that reflects the released energy of elastic vibrations (from 1 to 9.5 on the Richter scale).

The easiest way for science is to identify seismically dangerous zones and long-term forecasting of earthquakes for the next 10-15 years. To do this, researchers analyze the cyclical activation of the seismotectonic process: there is no reason to believe that in the next few hundred years the Earth will begin to behave differently than in a similar period of time in the past.

Is it possible to predict earthquakes

No, at least with sufficient accuracy to allow evacuation programs to be planned. And although most earthquakes occur in predictable locations along well-known geological faults, the reliability of short-term forecasts leaves much to be desired.

“We have models that show that in Southern California the risk of earthquakes of magnitude 7.5 or greater in the next 30 years is 38%. If these models are used to calculate the probability of earthquakes in the coming week, the probability drops to about 0.02%,” comments Thomas Jordan, director of the Southern California Earthquake Center.

This risk is quite small, but still not zero, and since the San Andreas transform fault passes through the state of California, local schools regularly conduct drills to prepare for a large earthquake.

Why are large earthquakes so difficult to predict?

Reliable predictions require identifying signals that would indicate an upcoming large earthquake. Such signals should be characteristic only of large earthquakes: weak and moderate tremors with a magnitude of up to 5 can lead to hanging objects swaying, glass rattling or plaster falling, which does not require evacuation of the population. However, in 5-10% of cases such tremors turn out to be foreshocks, which precede stronger earthquakes. According to statistics, foreshock activity is characteristic of 40% of medium and 70% of large earthquakes.

Seismologists have still not been able to identify specific events that regularly occur only before large earthquakes.

Today, a wide range of potential earthquake predictors have been studied, from increased radon concentrations in the air and unusual animal behavior to deformation of the earth's surface and changes in groundwater levels. But these anomalies are general: each of them can occur even before the weakest shocks.

Why are people not evacuated at the slightest risk of a major earthquake?

The main reason is the high probability of a false alarm. Thus, in 1975, in Haicheng (China), seismologists recorded an increase in the frequency of weak earthquakes and declared a general alarm on February 4 at 2 pm. After 5 hours and 36 minutes, an earthquake with a magnitude of more than 7 occurred in the city, many buildings were destroyed, but thanks to timely evacuation, the cataclysm occurred with virtually no casualties.

Unfortunately, such successful predictions could not be repeated in the future: seismologists predicted several large earthquakes that did not take place, and the shutdown of enterprises and evacuation of the population only resulted in economic losses.

How do earthquake early warning systems work?

Japan today has the best early warning system for earthquakes. The country is literally “strewn” with stations that, using sensitive equipment, record seismic waves, identify potential foreshocks and transmit information to the Meteorological Agency, which, in turn, immediately transmits it to TV, the Internet and mobile phones of citizens. Thus, by the time the second seismic wave arrives, the population has already been warned about the epicenter of the earthquake, its magnitude and the time of approach of the second wave.

Despite technological advances, even the Japanese warning system goes off after a natural disaster has occurred. But until researchers thoroughly study the physical processes associated with earthquakes, one cannot count on more. Residents of seismically active zones can only hope that seismometers will become more sensitive, and satellite observation will help speed up forecast times.

Nadezhda Guseva

Candidate of Geological and Mineralogical Sciences

Is it possible to predict earthquakes?

Predicting earthquakes is a difficult task. Vertical and horizontal displacements of blocks of the earth's crust cause deep earthquakes, which can reach catastrophic force. Low-hazard surface earthquakes occur due to the fact that the magmatic melt rising along cracks in the earth's crust stretches these cracks as it moves. The problem is that these two related but different causes of earthquakes have similar external manifestations.

Tongariro National Park, New Zealand

Wikimedia Commons

However, a team of scientists from New Zealand was able not only to distinguish traces of stretching of the earth's crust caused by magmatic and tectonic processes in the Tongariro deep fault zone, but also to calculate the rate of stretching arising from one and other processes. It has been established that in the area of ​​the Tongariro fault, magmatic processes play a secondary role, and tectonic processes have a decisive influence. The results of the study, published in the July issue of the Bulletin of the Geological Society of America, help clarify the risks of dangerous earthquakes in this popular tourist park, located 320 kilometers from the capital of New Zealand, Wellington, as well as in similar structures in other regions of the Earth.

Grabens and rifts

Tongariro is New Zealand's Yellowstone. Three “smoking mountains” - volcanoes Ruapehu (2797 meters), Ngauruhoe (2291 meters) and Tongariro (1968 meters), many smaller volcanic cones, geysers, lakes painted in blue and emerald colors, stormy mountain rivers together form a picturesque landscape of the national Tongariro Park. These landscapes are familiar to many because they served as natural settings for Peter Jackson’s film trilogy “The Lord of the Rings.”

By the way, the origin of these beauties is directly related to the peculiarities of the geological structure of the region: with the presence of parallel faults in the earth’s crust, accompanied by the “falling through” of the fragment located between the faults. This geological structure is called a graben. A geological structure that includes several extended grabens is called a rift.

Planetary-scale rift structures pass through the median axes of the oceans and form mid-ocean ridges. Large rifts serve as the boundaries of tectonic plates, which, like the hard segments that make up a turtle's shell, form the hard shell of the Earth, its crust.

New Zealand formed where the Pacific Plate is slowly subducting under the Australian Plate. The chains of islands that appear in such zones are called island arcs. On a planetary scale, rift zones are extension zones, and island arc zones are compression zones of the Earth's crust. However, on a regional scale, stresses in the earth's crust are not monotonic, and in each major compression zone there are local extension zones. As a very rough analogy of such local tensile zones, we can consider the occurrence of fatigue cracks in metal products. The Tongoriro Graben is such a local extension zone.

In New Zealand, due to its position in a zone of active geological processes on a planetary scale, about 20 thousand earthquakes occur every year, approximately 200 of them are strong.

Magma or tectonics?

Earthquake forecasting is difficult. Faults often serve as channels through which magma moves from deep levels to the surface. This process is also accompanied by local stretching of the earth's crust. In this case, magma does not always reach the earth's surface, and in some cases it can stop at a certain depth and crystallize there, forming a long and narrow magmatic body called a dike.

On the surface, extensions of the earth's crust caused by the intrusion of dikes (extensions of a magmatic nature) are often morphologically indistinguishable from extensions caused by the release of stresses arising due to the movement of blocks of the earth's crust relative to each other (extensions of a tectonic nature). But to predict earthquakes, it is critically important to distinguish between these two types of stretching, because earthquakes associated with the intrusion of dikes are near-surface and do not lead to catastrophic consequences, while earthquakes of a tectonic nature can cause a lot of trouble.

It was clear that both types of extension took place in the New Zealand rift system, and in particular in the Tongoriro graben, but there were two mutually contradictory opinions as to which of them predominated.

Threat of catastrophic earthquakes

The research, undertaken by a team including Geological Survey New Zealand and Auckland and Massey universities, was carried out to find a way to distinguish between magmatic and tectonic extension and clarify the risks of large and catastrophic earthquakes in Tongariro National Park.

The scientists used a combination of methods, including relative geochronology to determine the sequence of faults in the earth's crust and analysis of historical records of volcanic eruptions. The key stage of the study was the numerical modeling of the parameters of disturbances in the earth's crust that would arise as a result of the intrusion of dikes, and a careful comparison between the model and actually observed parameters.

The study concluded that the crust in the Tongoriro graben region is stretching by 5.8–7 mm per year due to tectonic events and by 0.4–1.6 mm per year due to volcanic eruptions and dyke intrusions. This means that magmatic processes are not the main cause of crustal movements and building codes must take into account the possibility of strong and catastrophic earthquakes. And the developed methodology can be used to assess the contribution of magmatic processes to the movements of the earth’s crust in similar structures in other regions of the Earth.

Hi all! Welcome to the pages of my blog about security. My name is Vladimir Raichev and today I decided to tell you what harbingers of earthquakes exist. Why, I wonder, do so many people become victims of earthquakes? Can't they be predicted?

Recently my students asked me this question. The question, of course, is not an idle one; I myself find it very interesting. In a textbook on life safety, I read that there are several types of earthquake forecasting:

1. Long term. Simple statistics, if you analyze earthquakes on seismic belts, you can identify a certain pattern in the occurrence of earthquakes. With an error of several hundred years, but will this really help us?
2. Medium term. The composition of the soil is studied (during earthquakes it changes) and with an error of several decades it can be assumed that an earthquake will occur. Has it become easier? I don't think so.
3. Short. This type of forecast involves tracking seismic activity and allows you to catch the beginning vibrations of the earth's surface. Do you think this forecast will help us?

However, the development of this problem is extremely difficult. Perhaps no science experiences such difficulties as seismology. If, when forecasting the weather, meteorologists can directly observe the state of air masses: temperature, humidity, wind speed, then the bowels of the Earth are accessible to direct observations only through boreholes.

The deepest wells do not reach even 10 kilometers, while earthquakes occur at depths of 700 kilometers. The processes that are associated with the occurrence of earthquakes can reach even greater depths.

Changing coastline position as a sign of an impending earthquake

Nevertheless, attempts to identify factors that precede earthquakes, although slowly, are still leading to positive results. It would seem that a change in the position of the coastline relative to ocean level can serve as a harbinger of earthquakes.

However, in many countries, under the same conditions, earthquakes were not observed, and vice versa - when the position of the coastline was stable, earthquakes did occur. This is apparently explained by the difference in the geological structures of the Earth.

Consequently, this feature cannot be universal for earthquake forecasts. But it should be noted that the change in the height of the coastline was the impetus for making special observations of the deformations of the earth’s crust using geodetic surveys and special instruments.

Changes in the electrical conductivity of rocks are another indicator of an incipient earthquake

Changes in the speed of propagation of elastic vibrations, electrical resistance and magnetic properties of the earth's crust can be used as precursors of earthquakes. Thus, in the regions of Central Asia, when studying the electrical conductivity of rocks, it was discovered that some earthquakes were preceded by a change in electrical conductivity.

During strong earthquakes, enormous energy is released from the depths of the Earth. It is difficult to admit that the process of accumulation of enormous energy before the rupture of the earth's crust, that is, an earthquake, proceeds subtly. Probably, over time, with the help of more advanced geophysical equipment, observations of these processes will make it possible to accurately predict earthquakes.

The development of modern technology, which now makes it possible to use laser beams for more accurate geodetic measurements, electronic computer technology for processing information from seismological observations, and modern ultra-sensitive instruments open up great prospects for seismology.

Radon release and animal behavior are warning signs of upcoming tremors

Scientists have discovered that before tremors, the content of radon gas in the earth's crust changes. This occurs, apparently, due to compression of the earth's rocks, as a result of which gas is displaced from great depths. This phenomenon was observed during repeated seismic shocks.

The compression of earthly rocks, obviously, can explain another phenomenon, which, unlike those listed, has given rise to many legends. In Japan, small fish of a certain variety have been observed to move to the surface of the ocean before an earthquake.

It is believed that animals in some cases sense the approach of earthquakes. However, it is practically difficult to use these phenomena as harbingers, because the comparison of animal behavior in ordinary situations and before an earthquake begins when it has already occurred. This sometimes gives rise to various unfounded judgments.

Work related to the search for earthquake harbingers is being carried out in a variety of directions. It was noted that the creation of large reservoirs at hydroelectric power plants in some seismically active zones of the USA and Spain contributes to an increase in earthquakes.

A specially created international commission to study the influence of large reservoirs on seismic activity suggested that the penetration of water into rocks reduces their strength, which can cause an earthquake.

Experience has shown that work to search for earthquake harbingers requires closer cooperation between scientists. The development of the problem of earthquake prediction has entered a new phase of more fundamental research based on modern technical means, and there is every reason to hope that it will be solved.

I recommend that you read my articles about earthquakes, for example, about the Messina earthquake in Italy, or the TOP of the most powerful earthquakes in the history of mankind.

As you can see, friends, predicting an earthquake is a very difficult task that is not always possible to accomplish. And with this I say goodbye to you. Don't forget to subscribe to the blog news to be among the first to know when new articles are released. Share the article with your friends on social networks, it’s a small thing for you, but it’s nice for me. I wish you all the best, bye bye.

20% of the territory of Russia belongs to seismically active areas (including 5% of the territory is subject to extremely dangerous 8-10 magnitude earthquakes).

Over the past quarter century, about 30 significant earthquakes, that is, with a magnitude of more than seven on the Richter scale, have occurred in Russia. 20 million people live in zones of possible destructive earthquakes in Russia.

Residents of the Far Eastern region of Russia suffer the most from earthquakes and tsunamis. The Pacific coast of Russia is located in one of the “hottest” zones of the “Ring of Fire”. Here, in the area of ​​transition from the Asian continent to the Pacific Ocean and the junction of the Kuril-Kamchatka and Aleutian island volcanic arcs, more than a third of Russia’s earthquakes occur; there are 30 active volcanoes, including such giants as Klyuchevskaya Sopka and Shiveluch. Here is the highest density of distribution of active volcanoes on Earth: for every 20 km of coastline there is one volcano. Earthquakes occur here no less often than in Japan or Chile. Seismologists usually count at least 300 significant earthquakes per year. On the seismic zoning map of Russia, the areas of Kamchatka, Sakhalin and the Kuril Islands belong to the so-called eight- and nine-point zone. This means that in these areas the intensity of shaking can reach 8 and even 9 points. Destruction may also result. The most destructive earthquake measuring 9.0 on the Richter scale occurred on Sakhalin Island on May 27, 1995. About 3 thousand people died, the city of Neftegorsk, located 30 kilometers from the epicenter of the earthquake, was almost completely destroyed.

Seismically active regions of Russia also include Eastern Siberia, where 7-9 point zones are distinguished in the Baikal region, Irkutsk region and the Buryat Republic.

Yakutia, through which the boundary of the Euro-Asian and North American plates passes, is not only considered a seismically active region, but is also a record holder: earthquakes with epicenters north of 70° N often occur here. As seismologists know, the bulk of earthquakes on Earth occur near the equator and in mid-latitudes, and in high latitudes such events are recorded extremely rarely. For example, on the Kola Peninsula, many different traces of high-power earthquakes have been discovered - mostly quite old. The forms of seismogenic relief discovered on the Kola Peninsula are similar to those observed in earthquake zones with an intensity of 9-10 points.

Other seismically active regions of Russia include the Caucasus, spurs of the Carpathians, and the coasts of the Black and Caspian Seas. These areas are characterized by earthquakes with a magnitude of 4-5. However, during the historical period, catastrophic earthquakes with a magnitude of more than 8.0 were also recorded here. Traces of a tsunami were also found on the Black Sea coast.

However, earthquakes can also occur in areas that cannot be called seismically active. On September 21, 2004, two series of tremors with a force of 4-5 points were recorded in Kaliningrad. The epicenter of the earthquake was 40 kilometers southeast of Kaliningrad near the Russian-Polish border. According to maps of general seismic zoning of the territory of Russia, the Kaliningrad region belongs to a seismically safe area. Here the probability of exceeding the intensity of such tremors is about 1% within 50 years.

Even residents of Moscow, St. Petersburg and other cities located on the Russian Platform have reason to worry. On the territory of Moscow and the Moscow region, the last of these seismic events with a magnitude of 3-4 occurred on March 4, 1977, on the nights of August 30-31, 1986 and May 5, 1990. The strongest known seismic tremors in Moscow, with an intensity of over 4 points, were observed on October 4, 1802 and November 10, 1940. These were “echoes” of larger earthquakes in the Eastern Carpathians.