It is known to all people, and even children, but what are the reasons that suddenly the ground under your feet begins to move and everything around collapses?
First of all, it must be said that earthquakes are conventionally divided into several types: tectonic, volcanic, landslide, artificial and man-made. We will briefly look at all of them right now. If you want to know, be sure to read to the end.
Tectonic causes of earthquakes
Most often, earthquakes occur due to the fact that they are in constant motion. The top layer of lithospheric plates is called tectonic plates. The platforms themselves move unevenly and constantly press on each other. However, they remain alone for a long time.
Gradually, the pressure increases, as a result of which the tectonic plate makes a sudden push. It is this that produces vibrations in the surrounding rock, which is why an earthquake occurs.
San Andreas Fault
Transform faults are huge cracks in the Earth where plates rub against each other. Many readers will be aware that the San Andreas Fault is one of the most famous and longest transform faults in the world. He is in .
Photo of the San Andreas fault Platforms moving along it cause destructive earthquakes in the cities of San Francisco and. Interesting fact: in 2015, Hollywood released a movie called “San Andreas Fault.” He talks about the corresponding disaster.
Volcanic causes of earthquakes
One of the causes of earthquakes is. Although they do not produce strong vibrations of the earth, they last quite a long time. The reasons for the tremors are related to the fact that deep in the bowels of the volcano the tension formed by lava and volcanic gases increases. As a rule, volcanic earthquakes last for weeks or even months.
However, history knows cases of tragic earthquakes of this type. An example is the Krakatoa volcano, located in Indonesia, which erupted in 1883.
Krakatoa still gets excited sometimes. Real photo. The force of its explosion was at least 10 thousand times greater than the force of . The mountain itself was almost completely destroyed, and the island split into three small parts. Two-thirds of the land disappeared under water, and what rose destroyed everyone who still had a chance to escape. More than 36,000 people died.
Landslide causes of earthquakes
Earthquakes caused by giant landslides are called landslides. They are local in nature, and their strength is usually small. But there are exceptions here too. For example, in 1970, a landslide with a volume of 13 million cubic meters descended from Huascaran at a speed of over 400 km/h. About 20,000 people died.
Technogenic causes of earthquakes
Earthquakes of this type are caused by human activity. For example, artificial reservoirs in places not intended for this by nature provoke pressure on the plates with their weight, which serves to increase the number and strength of earthquakes.
The same applies to the oil and gas industry, when large quantities of natural materials are extracted. In a word, man-made earthquakes occur when a person took something from nature from one place and transferred it to another without asking.
Artificial causes of earthquakes
From the name of this type of earthquake it is easy to guess that the blame for it lies entirely with man.
For example, in 2006 it tested a nuclear bomb, which caused a small earthquake recorded in many countries. That is, any activity of the inhabitants of the earth, which is obviously guaranteed to entail an earthquake, is an artificial cause of this type of disaster.
Is it possible to predict earthquakes?
Indeed it is possible. For example, in 1975, Chinese scientists predicted an earthquake and saved many lives. But this cannot be done with a 100% guarantee, even today. An ultra-sensitive device that records an earthquake is called a seismograph. The vibrations of the earth are recorded on the rotating drum by a recorder.
Seismograph Animals also feel anxious before earthquakes. Horses begin to rear up for no apparent reason, dogs bark strangely and crawl out of their holes to the surface.
Earthquake scale
Typically, the strength of earthquakes is measured using the Earthquake Scale. We will present all twelve points so that you have an idea of what it is.
- 1 point (invisible) - the earthquake is recorded exclusively by instruments;
- 2 points (very weak) - can only be noticed by domestic animals;
- 3 points (weak) - noticeable only in some buildings. Feels like driving over bumps in a car;
- 4 points (moderate) - noticed by many people, may cause movement of windows and doors;
- 5 points (quite strong) - glass rattles, hanging objects sway, old whitewash may crumble;
- 6 points (strong) - with this earthquake, slight damage to buildings and cracks in low-quality buildings are noted;
- 7 points (very strong) - at this stage the buildings suffer significant damage;
- 8 points (destructive) - destruction is observed in buildings, chimneys and cornices are falling, cracks of several centimeters can be seen on the mountain slopes;
- 9 points (devastating) - earthquakes cause collapses of some buildings, old walls collapse, and the speed of crack propagation reaches 2 centimeters per second;
- 10 points (destructive) - collapses in many buildings, in most - serious damage. The soil is riddled with cracks up to 1 meter wide, and there are landslides and landslides all around;
- 11 points (catastrophe) - large landslides in mountainous areas, numerous cracks and a picture of general destruction of most buildings;
- 12 points (severe catastrophe) - the relief is changing globally almost before our eyes. Huge collapses and total destruction of all buildings.
In principle, on a twelve-point earthquake scale, any catastrophe caused by tremors of the earth’s surface can be assessed.
Finally, it should be added that the true causes of the earthquake are quite difficult to establish. This happens because natural mechanisms are so complex that they have not yet been fully studied.
We have told you only the most related to such a disaster as an earthquake..
They demonstrated the terrifying power of these natural phenomena. Almost 16,000 people died and more than a million buildings were completely or partially destroyed. A year after these events, 330,000 people are still living in hotels or other temporary housing, unable to return home. Another 3,000 people are still missing. Giant tsunami waves generated by the earthquake flooded the power and cooling systems of three reactors at the Fukushima nuclear power plant.
Earthquakes cannot be stopped, but we know how they work. Scientists have developed networks of sensors to monitor the movement of the earth, changes in groundwater and magnetic fields that can indicate an impending earthquake. Engineers, meanwhile, have developed new forms of architecture to withstand earthquakes. So, without further ado, let's find out the most interesting facts about earthquakes.
1. The record depth at which the earthquake epicenter was recorded.
750 kilometers.
2. How many earthquakes occur per year?
3. Do earthquakes occur more often in warm weather?
4. What is the earth's crust made of?
The Earth's crust is broken into moving pieces called plates. These plates float on the dense rocks of the mantle, a sticky layer that lies between the planet's core and the Earth's crust. The most common rock in the crust that forms the Earth's continents is granite. This continental crust averages 35 km thick and is deepest beneath mountain ranges. The oceanic crust is thinner - six kilometers on average - and is mostly made of dense volcanic rocks such as basalt. Interestingly, granite consists of 75% oxygen and silicon. Basalt is denser because the silicon is contaminated with heavy elements such as iron.
5. How thick is the earth's crust?
from 5 to 70 kilometers.
6. Did the earthquake in Japan in 2011 really make the days shorter?
Yes, but you'll hardly notice it. Every day is now 1.8 microseconds shorter, according to NASA. The fact is that the Japanese earthquake accelerated the rotation of the Earth, changing its rotation around an imaginary line called an axis. The Earth's mass is balanced around its axis, and it wobbles as it rotates. This fluctuation is up to one meter per year due to the movement of glaciers and ocean currents. In 2011, an earthquake moved the ocean floor near Japan as much as 16 meters vertically and 50 meters horizontally—equivalent to the horizontal distance of an Olympic swimming pool! Shifts of the ocean floor increased the Earth's oscillations around its axis by 17 centimeters. And as the vibrations increased, the Earth accelerated its rotation. This principle will be better understood if we remember that a skater pulls his arms closer to his body in order to spin faster.
7. What is the shadow side of an earthquake?
The shadow zone is where seismographs cannot detect an earthquake after its seismic waves have passed through the Earth. The shadow zone is located on the Earth's surface at an angle of 104-140 degrees from the origin of the earthquake, and is not crossed by S-waves or direct P-waves. The shadow zone forms because S waves cannot pass through the Earth's liquid outer core, while P waves are refracted by the liquid core.
8. Where do earthquakes most often occur?
About 90 percent of earthquakes occur on the so-called Ring of Fire, a belt of seismic activity surrounding the Pacific Plate. The Ring of Fire is a massive subduction zone where the Pacific Plate collides with and sinks beneath other crustal plates. Most earthquakes have been observed in Japan, which lies on the Ring of Fire at the junction of the Pacific, Philippine, Eurasian and Okhotsk plates. Japan has a good earthquake monitoring network, and scientists can detect even small earthquakes. Indonesia's volcanic island chain probably experiences the highest number of earthquakes on land, but has fewer instruments to measure them.
9. Is it true that earthquakes occur more often in the morning?
10. What are tremors?
Tremors are another name for an earthquake. It also represents the vibration you experience during an earthquake.
11. How do scientists record the size of an earthquake?
Scientists use a seismograph to record earthquake waves called P and S waves. P waves travel faster than S waves and can travel through liquids. By measuring the delay between the P and S waves, scientists can calculate the distance the waves have traveled.
12. When was the earliest record of a major earthquake in history?
The first earthquake was described in China in 1177 BC. By the 17th century, accounts of the effects of earthquakes were published around the world.
13. What do the lines on a seismograph mean?
The wavy lines on the seismogram represent the recorded waves. The first large wavy line is P-waves, the second line is S-waves. If the latter is missing, the earthquake occurred on the other side of the planet.
14. Why do earthquakes cause tsunamis?
When two plates come into contact underwater, they exert pressure on each other, thereby creating pressure. There comes a time when one slab cannot stand it and slides off. As a result, the accumulated energy is released and an underwater earthquake occurs. A column of water is pushed upward, resulting in a tsunami on the surface of the ocean. Tsunamis are giant waves that can cross oceans at enormous speeds of up to 700 kilometers per hour and reach heights of 20 meters.
15. How do P and S waves move?
P waves (primary waves) are the fastest waves produced by an earthquake. They can pass through solid and molten rocks. P waves move in a spiral that resembles a Slinky spring toy.
S-waves (secondary waves) are 1.7 times slower than P-waves and can only travel through hard rock. However, they cause more damage because they are larger and shake the ground vertically and horizontally.
16. How long do earthquakes last?
10-30 seconds.
17. Do earthquakes occur only on Earth?
There is evidence of “Marsquakes” on Mars, as well as “Venerquakes” on Venus. Signs of earthquakes have also been observed on several of Jupiter's moons, as well as on (a moon of Saturn). In addition, tidal “moonquakes” have been discovered on the Moon, which are caused by the influence of Earth’s gravity. The moon also vibrates from meteorite impacts and tremors caused by the heating of the lunar surface after a two-week lunar night.
18. Can animals predict earthquakes?
It is not known for certain whether animals can predict earthquakes, but there are many stories about their strange behavior. One such story claims that hibernating snakes left their burrows a month before the earthquake that struck China in 1975.
It seems that natural disasters happen once every hundred years, and our vacation in one or another exotic country lasts only a few days.
Frequency of earthquakes of different magnitudes in the world per year
- 1 earthquake with a magnitude of 8.0 or higher
- 10 – with a magnitude of 7.0 – 7.9 points
- 100 – with a magnitude of 6.0 – 6.9 points
- 1000 - with a magnitude of 5.0 - 5.9 points
Earthquake intensity scale
Richter scale, points | Strength | Description |
Not felt | Not felt |
|
Very weak tremors | Sensible only to very sensitive people |
|
Only felt inside some buildings |
||
Intensive | Feels like slight vibration of objects |
|
Quite strong | Sensible to sensitive people on the street |
|
Felt by everyone on the street |
||
Very strong | Cracks may appear in the walls of stone houses |
|
Destructive | Monuments are moved from their places, houses are severely damaged |
|
Devastating | Severe damage or destruction of houses |
|
Destructive | Cracks in the ground can be up to 1m wide |
|
Catastrophe | Cracks in the ground can reach more than a meter. Houses are almost completely destroyed |
|
Catastrophe | Numerous cracks in the ground, collapses, landslides. The appearance of waterfalls, deviation of river flows. No structure can withstand |
Mexico City, Mexico
One of the world's most populous cities is known for its insecurity. In the 20th century, this part of Mexico felt the force of more than forty earthquakes, the magnitude of which exceeded 7 points on the Richter scale. In addition, the soil under the city is saturated with water, which makes high-rise buildings vulnerable in the event of natural disasters.
The most destructive earthquakes occurred in 1985, when about 10,000 people died. In 2012, the epicenter of the earthquake was in the southeastern part of Mexico, but vibrations were well felt in Mexico City and Guatemala, about 200 houses were destroyed.
The years 2013 and 2014 were also marked by high seismic activity in different parts of the country. Despite all this, Mexico City is still attractive to tourists due to its picturesque landscapes and numerous monuments of ancient culture.
Concepcion, Chile
Chile's second largest city, Concepción, located in the heart of the country near Santiago, regularly falls victim to tremors. In 1960, the famous Great Chilean earthquake with the highest magnitude in history, magnitude 9.5, destroyed this popular Chilean resort, as well as Valdivia, Puerto Montt, etc.
In 2010, the epicenter was again located near Concepción, about one and a half thousand houses were destroyed, and in 2013 the source sank to a depth of 10 km off the coast of central Chile (magnitude 6.6 points). However, today Concepcion does not lose popularity among both seismologists and tourists.
Interestingly, the elements have haunted Concepcion for a long time. At the beginning of its history, it was located in Penko, but due to a series of destructive tsunamis in 1570, 1657, 1687, 1730, the city was moved just south of its previous location.
Ambato, Ecuador
Today, Ambato attracts travelers with its mild climate, beautiful landscapes, parks and gardens, and massive fruit and vegetable fairs. Ancient buildings from the colonial era are intricately combined here with new buildings.
Several times this young city, located in central Ecuador, two and a half hours from the capital Quito, was destroyed by earthquakes. The most powerful tremors were in 1949, which leveled many buildings and claimed more than 5,000 lives.
Recently, seismic activity in Ecuador has continued: in 2010, an earthquake with a magnitude of 7.2 occurred southeast of the capital and was felt throughout the country; in 2014, the epicenter moved to the Pacific coast of Colombia and Ecuador, however, in these two cases there were no casualties .
Los Angeles, USA
Predicting destructive earthquakes in Southern California is a favorite pastime of geological survey specialists. The fears are fair: the seismic activity in this area is associated with the San Andreas Fault, which runs along the Pacific coast across the state.
History remembers the powerful earthquake of 1906, which claimed 1,500 lives. In 2014, the sun twice survived tremors (magnitude 6.9 and 5.1), which affected the city with minor destruction of houses and severe headaches for residents.
True, no matter how much seismologists frighten with their warnings, the “city of angels” Los Angeles is always full of visitors, and the tourist infrastructure here is incredibly developed.
Tokyo, Japan
It is no coincidence that a Japanese proverb says: “Earthquakes, fires and father are the most terrible punishments.” As you know, Japan is located at the junction of two tectonic layers, the friction of which often causes both small and extremely destructive tremors.
For example, in 2011, the Sendai earthquake and tsunami near the island of Honshu (magnitude 9) led to the death of more than 15,000 Japanese. At the same time, Tokyo residents have already become accustomed to the fact that several minor earthquakes occur every year. Regular fluctuations only impress visitors.
Despite the fact that most of the capital's buildings were built taking into account possible shocks, residents are defenseless in the face of powerful disasters.
Repeatedly throughout its history, Tokyo disappeared from the face of the earth and was rebuilt again. The Great Kanto Earthquake of 1923 turned the city into ruins, and 20 years later, rebuilt, it was destroyed by large-scale bombing by American air forces.
Wellington, New Zealand
The capital of New Zealand, Wellington, seems to be created for tourists: it has many cozy parks and squares, miniature bridges and tunnels, architectural monuments and unusual museums. People come here to take part in the grandiose Summer City Program festivals and admire the panoramas that became the film set for the Hollywood trilogy The Lord of the Rings.
Meanwhile, the city was and remains a seismically active zone, experiencing tremors of varying strength from year to year. In 2013, just 60 kilometers away, a magnitude 6.5 earthquake struck, causing power outages in many parts of the country.
In 2014, Wellington residents felt tremors in the northern part of the country (magnitude 6.3).
Cebu, Philippines
Earthquakes in the Philippines are a fairly common occurrence, which, of course, does not frighten those who like to lie on the white sand or snorkel in clear sea water. On average, more than 35 earthquakes with a magnitude of 5.0-5.9 points and one with a magnitude of 6.0-7.9 occur here per year.
Most of them are echoes of vibrations, the epicenters of which are located deep under water, which creates the danger of a tsunami. The 2013 earthquakes claimed more than 200 lives and caused serious damage in one of the most popular resorts in Cebu and other cities (magnitude 7.2).
Employees of the Philippine Institute of Volcanology and Seismology are constantly monitoring this seismic zone, trying to predict future disasters.
Sumatra Island, Indonesia
Indonesia is rightfully considered the most seismically active region in the world. The westernmost one in the archipelago has become especially dangerous in recent years. It is located at the site of a powerful tectonic fault, the so-called “Pacific Ring of Fire.”
The plate that forms the floor of the Indian Ocean is being squeezed under the Asian plate here as quickly as a human fingernail grows. The accumulated tension is released from time to time in the form of tremors.
Medan is the largest city on the island and the third most populous in the country. Two major earthquakes in 2013 seriously injured more than 300 local residents and damaged nearly 4,000 homes.
Tehran, Iran
Scientists have been predicting a catastrophic earthquake in Iran for a long time - the entire country is located in one of the most seismically active zones in the world. For this reason, the capital Tehran, home to more than 8 million people, was repeatedly planned to be moved.
The city is located on the territory of several seismic faults. An earthquake of magnitude 7 would destroy 90% of Tehran, whose buildings are not designed for such violent elements. In 2003, another Iranian city, Bam, was reduced to ruins by a 6.8 magnitude earthquake.
Today Tehran is familiar to tourists as the largest Asian metropolis with many rich museums and majestic palaces. The climate allows you to visit it at any time of the year, which is not typical for all Iranian cities.
Chengdu, China
Chengdu is an ancient city, the center of the southwestern Chinese province of Sichuan. Here they enjoy a comfortable climate, see numerous sights, and become immersed in the unique culture of China. From here they travel along tourist routes to the gorges of the Yangtze River, as well as to Jiuzhaigou, Huanglong and.
Recent events have reduced the number of visitors to the area. In 2013, the province experienced a powerful earthquake with a magnitude of 7.0, when more than 2 million people were affected and about 186 thousand houses were damaged.
Residents of Chengdu annually feel the effects of thousands of tremors of varying strength. In recent years, the western part of China has become especially dangerous in terms of seismic activity of the earth.
What to do in case of an earthquake
- If an earthquake catches you on the street, do not go near the eaves and walls of buildings that may fall. Stay away from dams, river valleys and beaches.
- If an earthquake strikes you in a hotel, open the doors to freely leave the building after the first series of tremors.
- During an earthquake, you should not run outside. Many deaths are caused by falling building debris.
- In case of a possible earthquake, it is worth preparing a backpack with everything you need for several days in advance. A first aid kit, drinking water, canned food, crackers, warm clothes, and washing supplies should be at hand.
- As a rule, in countries where earthquakes are a common occurrence, all local cellular operators have a system for alerting customers about an approaching disaster. While on vacation, be careful and observe the reaction of the local population.
- After the first shock there may be a lull. Therefore, all actions after it must be thoughtful and careful.
Earthquakes are a natural phenomenon that even today attracts the attention of scientists not only due to their little knowledge, but also due to their unpredictability, which can harm humanity.
What is an earthquake?
An earthquake is an underground tremors that can be felt by a person depending largely on the power of vibration of the earth's surface. Earthquakes are not uncommon and occur every day in different parts of the planet. Often, most earthquakes occur at the bottom of the oceans, which avoids catastrophic destruction within densely populated cities.
The principle of earthquakes
What causes earthquakes? Earthquakes can be caused by both natural causes and man-made ones.
Most often, earthquakes occur due to faults in tectonic plates and their rapid displacement. For a person, a fault is not noticeable until the moment when the energy generated from the rupture of rocks begins to break out to the surface.
How do earthquakes occur due to unnatural causes? Quite often, a person, through his carelessness, provokes the appearance of artificial tremors, which in their power are not at all inferior to natural ones. Among these reasons are the following:
- - explosions;
- - overfilling of reservoirs;
- - above-ground (underground) nuclear explosion;
- - collapses in mines.
The location where a tectonic plate breaks is the source of an earthquake. Not only the strength of the potential push, but also its duration will depend on the depth of its location. If the source is located 100 kilometers from the surface, then its strength will be more than noticeable. Most likely, this earthquake will lead to the destruction of houses and buildings. Occurring in the sea, such earthquakes cause tsunamis. However, the source can be located much deeper - 700 and 800 kilometers. Such phenomena are not dangerous and can only be recorded with the help of special devices - seismographs.
The place where the earthquake is most powerful is called the epicenter. It is this piece of land that is considered the most dangerous for the existence of all living things.
Studying earthquakes
A detailed study of the nature of earthquakes makes it possible to prevent many of them and make the life of the population living in dangerous places more peaceful. To determine the power and measure the strength of an earthquake, two basic concepts are used:
- - magnitude;
- - intensity;
The magnitude of an earthquake is a measure that measures the energy released during release from the source in the form of seismic waves. The magnitude scale allows you to accurately determine the origins of vibrations.
Intensity is measured in points and allows you to determine the ratio of the magnitude of tremors and their seismic activity from 0 to 12 points on the Richter scale.
Features and signs of earthquakes
Regardless of what causes an earthquake and in what area it is localized, its duration will be approximately the same. One push lasts on average 20-30 seconds. But history has recorded cases when a single shock without repetitions could last up to three minutes.
Signs of an approaching earthquake are the anxiety of animals, which, sensing the slightest vibrations on the surface of the earth, try to get away from the ill-fated place. Other signs of an imminent earthquake include:
- - the appearance of characteristic clouds in the form of oblong ribbons;
- - change in water level in wells;
- - malfunctions of electrical equipment and mobile phones.
How to behave during earthquakes?
How to behave during an earthquake to save your life?
- - Maintain reasonableness and calm;
- - When indoors, never hide under fragile furniture, such as a bed. Lie down next to them in the fetal position and cover your head with your hands (or protect your head with something extra). If the roof collapses, it will fall on the furniture and a layer may form, in which you will find yourself. It is important to choose strong furniture whose widest part is on the floor, i.e. this furniture cannot fall;
- - When outside, move away from tall buildings and structures, power lines that may collapse.
- - Cover your mouth and nose with a wet cloth to prevent dust and fumes from entering if any object catches fire.
If you notice an injured person in a building, wait until the tremors are over and only then get into the room. Otherwise, both people may be trapped.
Where do earthquakes not occur and why?
Earthquakes occur where tectonic plates break. Therefore, countries and cities located on a solid tectonic plate without faults do not have to worry about their safety.
Australia is the only continent in the world that is not at the junction of lithospheric plates. There are no active volcanoes and high mountains on it and, accordingly, there are no earthquakes. There are also no earthquakes in Antarctica and Greenland. The presence of the enormous weight of the ice shell prevents the spread of tremors across the surface of the earth.
The probability of earthquakes occurring on the territory of the Russian Federation is quite high in rocky areas, where the displacement and movement of rocks is most actively observed. Thus, high seismicity is observed in the North Caucasus, Altai, Siberia and the Far East.
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.
