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Instruction The frames of the film merge for us into continuous movement due to ...
Hundreds of thousands of earthquakes occur every year on our planet. Most of them are so small and insignificant that only special sensors can detect them. But, there are also more serious fluctuations: twice a month the earth's crust shudders strongly enough to destroy everything around.
Since most shocks of this magnitude occur at the bottom of the oceans, if they are not accompanied by a tsunami, people are not even aware of them. But when the land shudders, the elements are so destructive that the number of victims goes into the thousands, as happened in the 16th century in China (during earthquakes with a magnitude of 8.1, more than 830 thousand people died).
An earthquake is called tremors and vibrations of the earth's crust, caused by natural or artificially created causes (movement of lithospheric plates, volcanic eruptions, explosions). The consequences of shocks of great intensity are often catastrophic, second only to typhoons in the number of victims.
Unfortunately, on this moment scientists have not studied the processes that take place in the bowels of our planet so well, and therefore the earthquake forecast is rather approximate and inaccurate. Among the causes of earthquakes, experts identify tectonic, volcanic, landslide, artificial and man-made fluctuations of the earth's crust.
Tectonic
Most of the recorded earthquakes in the world arose as a result of movements of tectonic plates, when there is a sharp shift rocks. This can be either a collision with each other, or lowering a thinner plate under another.
Although this shift is usually small, and is only a few centimeters, the mountains located above the epicenter begin to move, which release tremendous energy. As a result, cracks form on the earth's surface, along the edges of which huge tracts of land begin to shift along with everything that is on it - fields, houses, people.
Volcanic
But volcanic fluctuations, although weak, continue for a long time. Usually they do not pose a particular danger, but catastrophic consequences were still recorded. As a result powerful eruption Krakatoa volcano in late XIX Art. half of the mountain was destroyed by the explosion, and the subsequent tremors were of such force that they split the island into three parts, plunging two thirds into the abyss. The tsunami that rose after that destroyed absolutely everyone who managed to survive before and did not have time to leave the dangerous territory.
landslide
It is impossible not to mention collapses and large landslides. Usually these concussions are not strong, but in some cases their consequences are catastrophic. So, it happened once in Peru, when a huge avalanche, causing an earthquake, descended from Mount Askaran at a speed of 400 km / h, and, having leveled more than one settlement, killed more than eighteen thousand people.
man-made
In some cases, the causes and consequences of earthquakes are often associated with human activities. Scientists have recorded an increase in the number of tremors in areas of large reservoirs. This is due to the fact that the collected mass of water begins to put pressure on the underlying earth's crust, and the water penetrating through the soil destroys it. In addition, an increase in seismic activity has been observed in oil and gas production areas, as well as in the area of mines and quarries.
artificial
Earthquakes can also be caused artificially. For example, after the DPRK tested a new nuclear weapon, in many places on the planet, sensors recorded earthquakes of moderate strength.
An underwater earthquake occurs when tectonic plates collide on the ocean floor or near the coast. If the focus is shallow, and the magnitude is 7 points, an underwater earthquake is extremely dangerous because it causes a tsunami. During the shudder of the sea crust, one part of the bottom sinks, the other rises, as a result of which the water, in an attempt to return to its original position, begins to move vertically, generating a series of huge waves going towards the coast.
Such an earthquake, together with a tsunami, can often have catastrophic consequences. For example, one of the strongest seaquakes occurred several years ago in Indian Ocean: as a result of underwater shocks, a large tsunami rose and, having fallen on the nearby coasts, led to the death of more than two hundred thousand people.
Start of shocks
The focus of an earthquake is a gap, after the formation of which the earth's surface instantly shifts. It should be noted that this gap does not occur immediately. First, the plates collide with each other, as a result of which friction occurs and energy is generated, which gradually begins to accumulate.
When the stress reaches its maximum and begins to exceed the force of friction, the rocks are torn apart, after which the released energy is converted into seismic waves moving at a speed of 8 km / s and causing the earth to vibrate.
The characteristics of earthquakes according to the depth of the epicenter are divided into three groups:
- Normal - epicenter up to 70 km;
- Intermediate - epicenter up to 300 km;
- Deep focus - the epicenter at a depth exceeding 300 km, typical for the Pacific Rim. The deeper the epicenter, the farther the seismic waves generated by the energy will reach.
Characteristic
An earthquake consists of several stages. The main, strongest shock is preceded by warning fluctuations (foreshocks), and after it, aftershocks begin, subsequent shaking, and the magnitude of the strongest aftershock is 1.2 less than that of the main shock.
The period from the beginning of foreshocks to the end of aftershocks may well last several years, as, for example, happened at the end of 19th century on the island of Lissa in the Adriatic Sea: it lasted three years and during this time scientists recorded 86 thousand shocks.
As for the duration of the main shock, it is usually short and rarely lasts more than a minute. For example, the most powerful shock in Haiti, which occurred a few years ago, lasted forty seconds - and that was enough to reduce the city of Port-au-Prince to ruins. But in Alaska, a series of aftershocks was recorded that shook the earth for about seven minutes, while three of them led to significant destruction.
It is extremely difficult, problematic and there are no 100% ways to calculate what kind of push will be the main one and will have the greatest magnitude. Therefore, strong earthquakes often take the population by surprise. So, for example, it happened in 2015 in Nepal, in a country where mild shaking was recorded so often that people simply did not pay attention to them. special attention. Therefore, a 7.9-magnitude ground tremor resulted in a large number of casualties, and weaker aftershocks of magnitude 6.6 that followed half an hour later and the next day did not improve the situation.
It often happens that the strongest shudders occurring on one side of the planet shake opposite side. For example, a magnitude 9.3 earthquake in the Indian Ocean in 2004 eased some of the increasing stress on the San Andreas Fault, which lies at the junction of lithospheric plates along the coast of California. It turned out to be of such strength that it slightly changed the appearance of our planet, smoothing out its bulge in the middle part and making it more rounded.
What is magnitude
One of the ways to measure the amplitude of oscillations and the amount of energy released is the magnitude scale (Richter scale), containing arbitrary units from 1 to 9.5 (it is often confused with the twelve-point intensity scale, measured in points). An increase in the magnitude of earthquakes by only one unit means an increase in the amplitude of oscillations by a factor of ten, and an increase in energy by a factor of thirty-two.
The calculations performed showed that the size of the epicenter during weak surface oscillations, both in length and vertically, is measured by several meters, when medium strength- kilometers. But earthquakes that cause catastrophes have a length of up to 1 thousand kilometers and go from the break point to a depth of up to fifty kilometers. Thus, the maximum recorded size of the epicenter of earthquakes on our planet was 1000 per 100 km.
The magnitude of earthquakes (Richter scale) looks like this:
- 2 - weak almost imperceptible fluctuations;
- 4 - 5 - although the shocks are weak, they can lead to minor damage;
- 6 - medium destruction;
- 8.5 is one of the strongest recorded earthquakes.
- The largest is the Great Chilean earthquake with a magnitude of 9.5, which gave rise to a tsunami, which, having overcome the Pacific Ocean, reached Japan, having overcome 17 thousand kilometers.
Focusing on the magnitude of earthquakes, scientists argue that out of tens of thousands of oscillations occurring on our planet per year, only one has a magnitude of 8, ten - from 7 to 7.9 and one hundred - from 6 to 6.9. Keep in mind that if the magnitude of the earthquake is 7, the consequences can be catastrophic.
intensity scale
To understand why earthquakes occur, scientists have developed an intensity scale based on external manifestations, as an impact on people, animals, buildings, nature. The closer the epicenter of earthquakes to the earth's surface, the greater the intensity (this knowledge makes it possible to give at least an approximate forecast of earthquakes).
For example, if the magnitude of the earthquake was eight, and the epicenter was at a depth of ten kilometers, the intensity of the earthquake will be from eleven to twelve points. But if the epicenter was located at a depth of fifty kilometers, the intensity will be less and will be measured at 9-10 points.
According to the scale of intensity, the first destruction can occur already with six-point shocks, when thin cracks appear in the plaster. An earthquake of eleven points is considered catastrophic (the surface of the earth's crust is covered with cracks, buildings are destroyed). The strongest earthquakes that can significantly change the appearance of the area are estimated at twelve points.
What to do in case of earthquakes
According to rough estimates of scientists, the number of people who have died in the world due to earthquakes over the past half a millennium exceeds five million people. Half of them are in China: it is located in a zone of seismic activity, and big number people (in the 16th century 830 thousand people died, in the middle of the last century - 240 thousand).
Such catastrophic consequences could have been prevented if earthquake protection had been well thought out at the state level, and the possibility of strong earthquakes was taken into account in the design of buildings: most people died under the rubble. Often, people living or staying in a seismically active zone do not have the slightest idea how exactly to act in conditions emergency and how you can save your life.
You need to know that if tremors caught you in a building, you need to do everything possible to get out into the open space as soon as possible, while using elevators is absolutely impossible.
If it is impossible to leave the building, and the earthquake has already begun, it is extremely dangerous to leave it, so you need to get up or doorway, or in the corner near bearing wall, or climb under a strong table, protecting your head soft pillow from objects that may fall from above. After the tremors are over, the building must be left.
If during the beginning of earthquakes a person was on the street, you need to move away from the house at least one third of its height and, avoiding tall buildings, fences and other buildings, move in the direction of wide streets or parks. It is also necessary to stay as far away from dangling electrical wires industrial enterprises because explosive materials or poisonous substances may be stored there.
But if the first tremors caught a person when he was in a car or public transport, you need to urgently leave vehicle. If the car is on open area on the contrary, stop the car and wait out the earthquake.
If it so happened that you were completely overwhelmed with debris, the main thing is not to panic: a person can survive without food and water for several days and wait until they find him. After catastrophic earthquakes, rescuers work with specially trained dogs, and they are able to smell life among the rubble and give a sign.
At further increase temperature in the bowels of the Earth rocks, despite high pressure melt, forming magma. This releases a lot of gases. This further increases both the volume of the melt and its pressure on the surrounding rocks. As a result, very dense, gas-rich magma tends to where the pressure is less. She fills the cracks in earth's crust, breaks and lifts the layers of its constituent rocks. Part of the magma, not reaching the earth's surface, solidifies in the thickness of the earth's crust, forming magmatic veins and laccoliths. Sometimes magma breaks out to the surface, and it erupts in the form of lava, gases, volcanic ash, rock fragments and hardened lava clots.
Volcanoes. Each volcano has a channel through which lava erupts (Fig. 24). This is vent, which always ends with a funnel-shaped extension - crater. The diameter of the craters ranges from several hundred meters to many kilometers. For example, the diameter of the Vesuvius crater is 568 m. Very large craters are called calderas. For example, the caldera of the Uzona volcano in Kamchatka, which is filled by Lake Kronotskoye, reaches 30 km in diameter.
The shape and height of volcanoes depend on the viscosity of the lava. Liquid lava spreads quickly and easily and does not form cone-shaped mountains. An example is the Kilauza volcano in the Hawaiian Islands. The crater of this volcano is a rounded lake with a diameter of about 1 km, filled with bubbling liquid lava. The level of lava, like water in a spring bowl, then falls, then rises, splashing over the edge of the crater.
Rice. 24. Sectional volcanic cone
Volcanoes with viscous lava are more widespread, which, when cooled, form a volcanic cone. The cone always has a layered structure, which indicates that the outpourings occurred repeatedly, and the volcano grew gradually, from eruption to eruption.
The height of volcanic cones varies from several tens of meters to several kilometers. For example, the Aconcagua volcano in the Andes has a height of 6960 m.
There are about 1500 active and extinct mountain volcanoes. Among them are such giants as Elbrus in the Caucasus, Klyuchevskaya Sopka in Kamchatka, Fujiyama in Japan, Kilimanjaro in Africa and many others.
Most of active volcanoes located around the Pacific Ocean, forming the Pacific "Ring of Fire", and in the Mediterranean-Indonesian belt. There are 28 active volcanoes known in Kamchatka alone, and there are more than 600 of them in total. Active volcanoes are naturally widespread - all of them are confined to mobile zones of the earth's crust (Fig. 25).
Rice. 25. Zones of volcanism and earthquakes
In the geological past of the Earth, volcanism was more active than it is now. In addition to the usual (central) eruptions, fissure eruptions occurred. From giant cracks (faults) in the earth's crust, stretching for tens and hundreds of kilometers, lava erupted onto the earth's surface. Solid or patchy lava covers were created, leveling the terrain. The thickness of the lava reached 1.5-2 km. This is how lava plains. Examples of such plains are individual sections of the Central Siberian Plateau, the central part of the Deccan Plateau in India, the Armenian Highlands, and the Columbia Plateau.
Earthquakes. The causes of earthquakes are different: volcanic eruption, landslides in the mountains. But the strongest of them arise as a result of movements of the earth's crust. Such earthquakes are called tectonic. They usually originate at great depths, at the boundary between the mantle and the lithosphere. The origin of an earthquake is called hypocenter or hearth. On the Earth's surface, above the hypocenter, is epicenter earthquakes (Fig. 26). Here, the strength of the earthquake is greatest, and with distance from the epicenter, it weakens.
Rice. 26. Hypocenter and epicenter of an earthquake
The earth's crust is constantly shaking. Over 10,000 earthquakes are observed during the year, but most of them are so weak that they are not felt by humans and are recorded only by instruments.
The strength of earthquakes is measured in points - from 1 to 12. Powerful 12-point earthquakes are rare and are catastrophic. During such earthquakes, deformations occur in the earth's crust, cracks, shifts, faults, landslides in the mountains and dips in the plains are formed. If they occur in densely populated areas, then there is great destruction and numerous human casualties. The largest earthquakes in history are the Messinian (1908), Tokyo (1923), Tashkent (1966), Chilean (1976) and Spitak (1988). In each of these earthquakes, dozens, hundreds and thousands of people died, and cities were destroyed almost to the ground.
In the lessons of natural history, we study volcanoes and earthquakes. We already know the basic concepts - the types and structure of volcanoes, why and how they erupt, where earthquakes most often occur and why they are dangerous ... 
Since ancient times, volcanoes and earthquakes have been considered the most massive and destructive natural phenomena, but at the same time, especially volcanoes, attract and fascinate with their strength and power. Every year one of them wakes up and destroys everything around, bringing destruction, death and material losses to people. However, despite their fear, they
attract the attention of thousands of tourists; settlements and even large cities are being built around many active volcanoes.
The best of the best...
the most beautiful considered one of the most active active volcanoes on Earth and the youngest of the Hawaiian volcanoes - Kilaue, it is located in the state of Hawaii, USA. The eruption of this volcano has been going on for 28 years, and it is the largest (about 4.5 km in diameter of the crater) active on Earth. Here you can admire intricately frozen lava and "lunar" landscapes. Tourists are allowed to the volcano. Kilaue is believed to be the home of Pele, the Hawaiian goddess of volcanoes. Lava formations are named after her - "Pele's tears" (drops of lava that cooled in the air and took the form of a tear) and "Pele's hair" (filaments of volcanic glass formed as a result of the rapid cooling of lava when flowing into the ocean). 
Interesting Facts.
When something happens eruption, this means not only the formation of ash clouds, which can prevent sunlight from entering the region, and cause a few days of cooling. It also releases sulfur gases. When they are ejected to the level of the stratosphere, aerosols from sulfuric acid are formed, they spread like a blanket over the entire planet. Since these aerosols are above the rain level, they are not washed out. They linger there reflecting sunlight and cooling the surface of the earth.
On average, every year on our planet there are about a million tremors. Most of them, fortunately, are almost imperceptible and can only be recorded with the help of sensitive instruments, but some shocks are of considerable force. On average, 15 to 25 strong earthquakes occur annually in the world.
10 most catastrophic volcanic eruptions
Volcano Unzen (Unzen), 1792
The largest eruption of the Unzen volcano occurred in 1792. From the volcanic eruption, earthquake and, as a result, the occurrence of a tsunami, 15,000 people died.
200 years after this eruption, the volcano was calm.
In 1991, the volcano became active again, in the same year there was an eruption with the release of lava, while 43 people died, including a group of scientists and journalists. The Japanese authorities were forced to evacuate thousands of residents. The volcano was active, ejecting lava and ash until about 1995. Since 1995, the activity has decreased and at the moment it is in a static state.
El Chichon Volcano, Mexico, 1982
The eruption of the El Chichon volcano in 1982, led to the death of 2,000 residents of nearby areas in the state of Chiapas, Mexico. After the eruption, a lake filled with chamois formed in the crater of the volcano.
A feature of the eruption of this volcano was that a large amount of aerosol was thrown into the atmosphere, about 20 million tons in this aerosol was the content of sulfuric acid.
The cloud entered the stratosphere and increased its average temperature by 4 C, and the destruction of the ozone layer was also observed.
Mount Pinatubo, Philippines, 1991
The 1991 eruption of Mount Pinatubo in the Philippines was the second largest eruption of the 20th century. The volcanic rating index was 6.
This is more than the eruption of St. Helens in 1980, but less than Tambora in 1815. Pinatubo, on June 15, 1991, ejected about two and a half cubic kilometers of matter, including lava, ash and toxic gases. In total, about 10 square kilometers of matter was ejected during the eruption. About 800 people died as a result of the eruption.
Volcano St. Helens, USA, 1980
On May 18, 1980, Mount St. Helens erupted in the United States. The volcanic eruption killed 57 people (according to other sources, 62 people).
The release of gases into the atmosphere reached a height of 24 kilometers, before the eruption there was an earthquake of magnitude 5.1 points, which caused a huge landslide.
The eruption lasted 9 hours. The released energy can be compared to the energy of an explosion of 500 atomic bombs dropped on Hiroshima.
Volcano Nevada del Ruiz, Colombia, 1985
The eruption of the Nevada del Ruiz volcano in 1985 killed 20,000 people in the nearby village of Armero. It is the second most fatal volcano in the 20th century.
The volcanic eruption melted the glacier on it, and the mudflow mass completely destroyed Armero.
But the tragedy happened first in the village of Chinchina - the authorities did not have time to completely evacuate the inhabitants and 2,000 people died. The total death toll is estimated at 23,000 to 25,000.
Kilauea Volcano, USA, 1983 (present)
The Kilauea volcano may not be the most destructive, but its peculiarity is that it erupts continuously for over 20 years, making it one of the most active volcanoes in the world. According to the diameter of the crater (4.5 km), the volcano is considered the largest in the world.
Vesuvius exploded in 79, he buried the entire city of Pompeii under a veil of ash and pumice, which fell from the sky during the day. Ash layer reached 3 meters. According to modern estimates, 25,000 people became victims of the volcano. Excavations were carried out on the site of the city of Pompeii, such a number of victims was caused by the fact that people began to leave their homes not immediately, but tried to pack and save their property.
Since 79, the volcano has erupted dozens of times, most recently in 1944.
The Pele volcano exploded on the Caribbean island of Martinique in 1902, killing 29,000 people and destroying the entire city of Saint-Pierre. For several days, the volcano spewed gases and a small part of the ash, the inhabitants saw it, and on May 8, Pele exploded.
Witnesses on ships, in the immediate vicinity of the coast, described the sudden appearance of a massive cloud in the form of a mushroom, filled with fiery hot ash and volcanic gases, emissions covered the island in a matter of seconds.
Only two people survived the explosion of the volcano.
Volcano Krakatoa, Indonesia, 1883
The explosion of Krakatoa in 1883 can be compared to the power of 13,000 atomic bombs.
Over 36,000 people died. The height of the ejected ash reached 30 km. After the eruption, the island seemed to have formed, that is, the island itself fell into the void under the volcano, all this was covered with masses of ocean waters. Since the surface temperature was high and the sinking of the land was fast, this led to the emergence (formation) of a tsunami wave that moved towards the island of Sumatra, which led to the death of more than 2,000 people on it.
At the moment, a new active volcano has formed on the site of the old volcano, which is growing in height by 6-7 meters per year.
Volcano Tambora, Indonesia, 1815
The Tambora volcano eruption was the largest volcanic eruption ever recorded on the planet.
10,000 people died instantly under lava flows and from poisoning by toxic gases.
The total number of deaths from the volcano and the tsunami is about 92,000 people, not counting those who died from the famine that followed.
The scale of the eruption is evidenced by the fact that the amount of substance released into the earth's atmosphere was so large that there was no summer in the northern hemisphere in 1816.
The thing is that particles of matter reflected the Sun's rays and interfered with the warming of the Earth.
The consequence of the eruption was famine around the world.
The power of the eruption was 7 points on the scale of volcanic eruptions.
August 24-25, 79 AD an eruption occurred that was considered extinct Mount Vesuvius, located on the shores of the Gulf of Naples, 16 kilometers east of Naples (Italy). The eruption led to the death of four Roman cities - Pompeii, Herculaneum, Oplontius, Stabia - and several small villages and villas. Pompeii, located 9.5 kilometers from the crater of Vesuvius and 4.5 kilometers from the base of the volcano, was covered with a layer of very small pieces of pumice about 5-7 meters thick and covered with a layer of volcanic ash. With the onset of night, lava flowed from the side of Vesuvius, everywhere fires started, the ashes made it hard to breathe. On August 25, along with the earthquake, a tsunami began, the sea receded from the coast, and a black thundercloud hung over Pompeii and the surrounding cities, hiding Cape Mizensky and the island of Capri. Most of the population of Pompeii was able to escape, but about two thousand people died from poisonous sulfurous gases on the streets and in the houses of the city. Among the victims was the Roman writer and scholar Pliny the Elder. Herculaneum, located seven kilometers from the crater of the volcano and about two kilometers from its sole, was covered with a layer of volcanic ash, the temperature of which was so high that all wooden objects were completely charred. The ruins of Pompeii were accidentally discovered at the end of the 16th century, but systematic excavations began only in 1748 and are still ongoing, along with reconstruction and restoration.
March 11, 1669 there was an eruption Mount Etna in Sicily, which lasted until July of that year (according to other sources, until November 1669). The eruption was accompanied by numerous earthquakes. Lava fountains along this crack gradually shifted downward, and the largest cone formed near the city of Nikolosi. This cone is known as Monti Rossi (Red Mountain) and is still clearly visible on the slope of the volcano. Nicolosi and two nearby villages were destroyed on the first day of the eruption. In another three days, the lava flowing down the slope to the south destroyed four more villages. At the end of March, two larger cities were destroyed, and in early April, lava flows reached the outskirts of Catania. Lava began to accumulate under the fortress walls. Part of it flowed into the harbor and filled it. April 30, 1669 lava flowed through upper part fortress walls. The townspeople built additional walls across the main roads. This made it possible to stop the progress of the lava, but the western part of the city was destroyed. The total volume of this eruption is estimated at 830 million cubic meters. Lava flows burned 15 villages and part of the city of Catania, completely changing the configuration of the coast. According to some sources, 20 thousand people, according to others - from 60 to 100 thousand.
October 23, 1766 on the island of Luzon (Philippines) began to erupt mayon volcano. Dozens of villages were swept away, incinerated by a huge lava flow (30 meters wide), which descended the eastern slopes for two days. Following the initial explosion and lava flow, Mayon volcano continued to erupt for another four days, spewing large amounts of steam and watery mud. Greyish-brown rivers, 25 to 60 meters wide, crashed down the slopes of the mountain in a radius of up to 30 kilometers. They completely swept away roads, animals, villages with people (Daraga, Kamalig, Tobako) on their way. More than 2,000 residents died during the eruption. Basically, they were swallowed up by the first lava flow or secondary mud avalanches. For two months, the mountain spewed ash, poured lava into the surrounding area.
April 5-7, 1815 there was an eruption Volcano Tambora on the Indonesian island of Sumbawa. Ashes, sand and volcanic dust were thrown into the air to a height of 43 kilometers. Stones up to five kilograms in weight scattered over a distance of up to 40 kilometers. The Tambora eruption affected the islands of Sumbawa, Lombok, Bali, Madura and Java. Subsequently, under a three-meter layer of ash, scientists found traces of the fallen kingdoms of Pekat, Sangar and Tambora. Simultaneously with the volcanic eruption, a huge tsunami 3.5-9 meters high was formed. Receding from the island, the water hit the neighboring islands and drowned hundreds of people. Directly during the eruption, about 10 thousand people died. At least 82 thousand more people died from the consequences of the catastrophe - hunger or disease. Ashes that covered Sumbawa with a shroud destroyed the entire crop and fell asleep irrigation system; acid rain poisoned the water. Within three years after the eruption of Tambora, the entire Earth enveloped in a veil of particles of dust and ash, reflecting part sun rays and cooling the planet. The following year, 1816, Europeans felt the effects of a volcanic eruption. He entered the annals of history as "a year without a summer". average temperature in the Northern Hemisphere fell by about one degree, and in some areas even by 3-5 degrees. From spring and summer frosts on the soil suffered large areas crops, and famine began in many territories.
August 26-27, 1883 there was an eruption Krakatoa volcano located in the Sunda Strait between Java and Sumatra. From the tremors on the nearby islands, houses collapsed. On August 27, at about 10 am, there was a giant explosion, an hour later - a second explosion of the same force. More than 18 cubic kilometers of rock fragments and ash shot up into the atmosphere. The tsunami waves caused by the explosions instantly swallowed up cities, villages, forests on the coast of Java and Sumatra. Many islands disappeared under water along with the population. The tsunami was so powerful that it bypassed almost the entire planet. In total, 295 cities and villages were swept off the face of the earth on the coasts of Java and Sumatra, more than 36 thousand people died, hundreds of thousands were left homeless. The shores of Sumatra and Java have changed beyond recognition. On the coast of the Sunda Strait fertile soil was washed down to the rocky base. Only a third of the island of Krakatoa survived. In terms of the amount of water and rock displaced, the energy of the Krakatoa eruption is equivalent to the explosion of several hydrogen bombs. The strange glow and optical phenomena persisted for several months after the eruption. In some places above the Earth, the sun seemed blue and the moon bright green. And the movement in the atmosphere of dust particles thrown out by the eruption allowed scientists to establish the presence of a "jet" flow.
May 8, 1902 Mont Pelee volcano located in Martinique, one of the islands caribbean, literally torn to pieces - four strong explosions sounded like cannon shots. They threw out a black cloud from the main crater, which was pierced by flashes of lightning. Since the emissions did not go through the top of the volcano, but through side craters, then all volcanic eruptions of this type have since been called "Peleian". Superheated volcanic gas, due to its high density and high speed movement, creeping above the earth itself, penetrated into all the cracks. A huge cloud covered the area of complete destruction. The second zone of destruction stretched for another 60 square kilometers. This cloud, formed from super-hot steam and gases, weighed down by billions of particles of incandescent ash, moving at a speed sufficient to carry rock fragments and volcanic eruptions, had a temperature of 700-980 ° C and was able to melt glass. Mont Pele erupted again - on May 20, 1902 - with almost the same force as on May 8. The volcano Mont-Pele, having scattered to pieces, destroyed one of the main ports of Martinique, Saint-Pierre, along with its population. 36 thousand people died instantly, hundreds of people died from side effects. The two survivors have become celebrities. Shoemaker Leon Comper Leander managed to escape within the walls own house. He miraculously survived, although he received severe burns to his legs. Louis Auguste Cypress, nicknamed Samson, was in a prison cell during the eruption and sat there for four days, despite severe burns. After being rescued, he was pardoned, soon he was hired by the circus and was shown during performances as the only surviving resident of Saint-Pierre.
June 1, 1912 eruption began Katmai volcano in Alaska, which has been dormant for a long time. On June 4, ash material was thrown out, which, mixed with water, formed mud flows, on June 6 there was an explosion of colossal force, the sound of which was heard in Juneau for 1200 kilometers and in Dawson for 1040 kilometers from the volcano. Two hours later there was a second explosion of great force, and in the evening a third. Then, for several days, an eruption of a colossal amount of gases and solid products went on almost continuously. During the eruption, about 20 cubic kilometers of ash and debris escaped from the mouth of the volcano. The deposition of this material formed a layer of ash from 25 centimeters to 3 meters thick, and much more near the volcano. The amount of ash was so great that for 60 hours there was complete darkness around the volcano at a distance of 160 kilometers. On June 11, volcanic dust fell in Vancouver and Victoria at a distance of 2200 km from the volcano. AT upper layers atmosphere, it spread throughout the territory North America and fell into in large numbers in pacific ocean. whole year small particles ash moved in the atmosphere. Summer on the entire planet turned out to be much colder than usual, since more than a quarter of the sun's rays falling on the planet were retained in the ashy curtain. In addition, in 1912 surprisingly beautiful scarlet dawns were observed everywhere. A lake with a diameter of 1.5 kilometers formed on the site of the crater - the main attraction of the lake formed in 1980 national park and the Katmai Wildlife Sanctuary.
December 13-28, 1931 there was an eruption volcano Merapi on the island of Java in Indonesia. For two weeks, from December 13 to 28, the volcano erupted a lava flow about seven kilometers long, up to 180 meters wide and up to 30 meters deep. The white-hot stream burned the earth, burned the trees and destroyed all the villages in its path. In addition, both sides of the volcano exploded, and the erupted volcanic ash covered half of the island of the same name. During this eruption, 1,300 people died. The eruption of Mount Merapi in 1931 was the most destructive, but far from the last.
In 1976, a volcanic eruption killed 28 people and destroyed 300 houses. Significant morphological changes taking place in the volcano caused another disaster. In 1994, the dome that had formed in previous years collapsed, and the resulting massive release of pyroclastic material forced local population leave their villages. 43 people died.
In 2010, the number of victims from the central part of the Indonesian island of Java was 304 people. The death toll included those who died from exacerbations of lung and heart diseases and other chronic diseases caused by ash emissions, as well as those who died from injuries.
November 12, 1985 eruption began Volcano Ruiz in Colombia, which was considered extinct. On November 13, several explosions were heard one after another. The power of the strongest explosion, according to experts, was about 10 megatons. A column of ash and rock fragments rose into the sky to a height of eight kilometers. The eruption that began caused the instantaneous melting of vast glaciers and eternal snows lying on the top of the volcano. The main blow fell on the city of Armero located 50 kilometers from the mountain, which was destroyed in 10 minutes. Of the 28.7 thousand inhabitants of the city, 21 thousand died. Not only Armero was destroyed, but also a number of villages. Badly affected by the eruption are settlements like Chinchino, Libano, Murillo, Casabianca and others. Mudflows damaged oil pipelines, fuel supply to the southern and western parts of the country was cut off. As a result of the sudden melting of snow lying in the mountains of Nevado Ruiz, nearby rivers burst their banks. Powerful streams of water washed away roads, demolished power lines and telephone poles, and destroyed bridges. According to the official statement of the Colombian government, as a result of the eruption of the Ruiz volcano, 23 thousand people died and went missing, about five thousand were seriously injured and maimed. About 4,500 residential buildings were completely destroyed and administrative buildings. Tens of thousands of people were left homeless and without any means of subsistence. The Colombian economy has suffered significant damage.
June 10-15, 1991 there was an eruption Mount Pinatubo on the island of Luzon in the Philippines. The eruption began quite rapidly and was unexpected, as the volcano came into a state of activity after more than six centuries of dormancy. On June 12, the volcano exploded, sending a mushroom cloud into the sky. Streams of gas, ash and rocks melted to a temperature of 980 ° C poured down the slopes at a speed of up to 100 kilometers per hour. For many kilometers around, all the way to Manila, day turned into night. And the cloud and the ash falling from it reached Singapore, which is 2.4 thousand kilometers away from the volcano. On the night of June 12 and the morning of June 13, the volcano erupted again, throwing ash and flame into the air for 24 kilometers. The volcano continued to erupt on June 15 and 16. Mud streams and water washed away houses. As a result of numerous eruptions, about 200 people died and 100 thousand were left homeless
The material was prepared on the basis of information from open sources
