Volcanoes. What are volcanoes: volcanic hazard? The meaning and interpretation of the word vulkany vulkanicheskaja opasnost, definition of the term

Signs of pregnancy after embryo implantation

A volcano is a hole or crack in the surface of the earth's crust through which molten, solid, or gaseous substances are released. The main products of the eruption are molten or solid minerals from the silicate group and gases. The nature of the erupted products varies greatly depending on the physical conditions and the chemical composition of the molten matter in the depths of the earth's crust (magma). Volcanoes do not exist only on Earth; for example, volcanoes on Triton, the largest of Neptune's two moons, were recently found to spew fountains of nitrogen.

In the city of Surabaya, tourists can use consular assistance from the Honorary Consulate of the Republic of India. An alternative could be the transfer from Padangbei to Lombok, and from there, a flight to Jakarta for interconnection. Indonesia has about 130 volcanoes, the highest of all earthly lands. Many of them are highly active, although there may be months for a real eruption.

V recent times activity of Italian volcanoes, Etna and Vesuvius. Campi Fregrey is a volcanic caldera with a diameter of 13 kilometers and is located west of Naples and about 35 kilometers from Vesuvius. One of the most dangerous volcanoes in Mexico is the Colima volcano. The latter happened a few days ago, half an hour after midnight.

The most seismically active zone on Earth - Ring of Fire, belt active volcanoes, around the Pacific Ocean. Volcanoes are located at the junctions of tectonic plates, along the edges of continents. Many major cities in the world are located in areas where the danger of earthquakes and volcanic eruptions is great.

VOLCANO FORGE

It is not surprising that volcanoes, like other catastrophic unpredictable phenomena, have been attributed to supernatural power since ancient times. The very word "volcano" comes from the name of the island of Vulcano, a small island north of Sicily. There were frequent eruptions, so the Romans believed that there was the forge of Vulcan - the god of fire and weaponsmith.

China is famous for its insane construction, consuming more fresh concrete there than in the rest of the world. Old buildings have to retreat sometimes. In this case, there were 19 prefabricated houses reaching 12 floors. Explosions and explosions are fairly common in space. Some explosions also affect the distance of many light years. Even a small body like Earth knows very well what explosions are.

The army wanted to demonstrate relative safety nuclear weapons during the period of fear of radioactive fallout. Imagine that you are standing on a beach and the sea suddenly disappears. It looks like it is returning to the horizon. On the coast there is only a bare bottom covered with algae and corals. At such a moment, it is time to head to the nearest hill. This is how a giant destructive wave called a tsunami goes.

DISTRIBUTION OF VOLCANOES ON THE PLANET

Currently, there are more than 1,500 active volcanoes on Earth. They are usually located near the ocean shores - most of the volcanoes on the planet are concentrated at the edges of the continents around the Pacific Ocean (Ring of Fire). There are also exceptions to this rule - for example, volcanoes in the Hawaiian Islands. The location of volcanoes depends on global tectonics - the movement of lithospheric plates, solid fragments from 10 to 80 km thick that make up the upper layer of the earth's surface.

Last year, the Sicilian volcano Etna was very active. It exploded for the last time in late December in a stunning cloud of fire and lightning. The volcanic explosion was a stunning sight that showed an extremely rare phenomenon - volcanic lightning... The people of the east coast of Sicily don't like the sight either.

The warning that boiling oil should not be extinguished with water is generally known. But what happens if we don't follow this rule? It will show you an immersive slow motion video. Explosive vapors will literally cause a flame to burst.

PLATE BOUNDARIES

Some of these plates diverge in different directions, others approach each other, and still others slide along each other. Volcanoes are usually located along plate boundaries, especially where they converge or diverge. At diverging (divergent) boundaries, tectonic plates stretch, become thinner, as a result of which the hot semi-molten material of the mantle rises upward along the cracks and melts completely, forming magma. Magma can break through plates and splash to the surface in several places at once, and volcanoes such as Kilimanjaro, Mount Kenya and Ol Doinyo Lengai are located along the Rift Valley.

In the neighboring houses, in addition to bankers, hundreds of envoys, scribes, secretaries and officials worked. Every day around noon, crowds of these people filled the street as they hurried to lunch. In this bustle, the horse-drawn carriage was completely lost with the tarpaulin-covered car.

Volcano Agun definitely gives its name. In addition to dust, lava flows out. The authorities ordered the immediate evacuation of the endangered and declared the highest level of danger. Airports are closed for the second day in a row, disrupting more than 445 flights.

Local authorities have already announced the most high level threats on Monday. The main reason was that the volcano was spewing out streams of magma other than dust, the Geological Agency's Department of Energy and Mineral Resources said. The airport is likely to open on Wednesday's fastest morning, as long as conditions don't threaten the traveler.

VOLCANOES OF THE MIDDLE OCEAN RIDGE

Where slabs open especially quickly, Earth's crust becomes so thin that it cracks over a long distance, and along the crack along its entire length, a continuous chain of active volcanoes arises. This process forms mid-ocean ridges, such as the Mid-Atlantic Ridge, from Jan Mayen Island east of Greenland to Bouvet Island in the South Atlantic. Small eruptions occur every now and then along the entire ridge. They usually occur in fissures up to 15 km long or in isolated volcanoes located in the rift zone in the middle of the ridge.

Bali airport was closed Monday morning for cancellation, Indonesia's Ministry of Transport said. There are thousands of tourists waiting for him to leave the island. Airplanes flying to Bali went to the airports of Jakarta, Surabaya and Singapore.

On Monday, authorities raised the warning level on the Indonesian island of Bali to the fourth highest level due to the violent eruption of Mount Agung. The populations inhabited 10 km from the volcano were called up for evacuation. Lombok's local airport has been closed.

From time to time, within 12 kilometers of the crater, explosions can be heard. At night, you can see the pillars of fire. Volcanic ash covered a thick layer of volcanic ash. Government officials ensure that tourists can feel safe but should avoid areas within 10 kilometers of the crater. The largest resorts in Bali - Kuta and Seminyak - are located about 70 km from the volcano.

ERUPTIONS IN ICELAND

On the island of Iceland, located in the middle Atlantic Ocean, where the mid-ocean ridge comes to the surface, almost all of the erupted magma, or lava, is liquid in nature. But the volume of the flowing lava is extremely large, because in this place under the ridge there is an upward heat flow from the mantle (the so-called hot zone). In 1783-1784, during the eruption from the Laki crack, the longest lava outpouring in history occurred - the lava flow moved 70 km from the place of origin. The accompanying emissions of sulfur-containing gases led to climate change, and in the years that followed, winters in northwest Europe were unusually harsh. In Iceland, agricultural crops and livestock were killed, and a terrible famine began. About 25% of Iceland's population died from hunger and disease.

So far, 40,000 residents have been evacuated. Not all of them were evacuated, said Ain Sutopo, a spokesman for the Indonesian natural disasters... - Some people didn't want to leave their animals. Others do not feel threatened, he added, and then gave assurances that these people might have to force themselves to leave the threatened territory.

At the beginning of this year, the area of ​​the volcano left more than 140 thousand. people, of which 25 thousand. is still in temporary shelters. In late September, the authorities allowed some of them to return. But on Tuesday, Agung found out himself again. Authorities have called on people who live within 7.5 miles of the crater to leave their homes and go to safety.

HOT ZONES

Centers of volcanic activity are often found near "hot zones" in the middle of tectonic plates. One such zone is the Hawaiian Islands, located in the middle of the Pacific Plate. Nearly all eruptions associated with hot zones are moderately violent but extremely long-lasting. For example, the eruption of the Puuoo volcano on the Hawaiian island of Kilauea lasted 16 years. The lava was very liquid and therefore covered huge areas.

Next, more violent eruptions occurred on Saturday night and three times on Sunday, when Agung threw out volcanic ash at an altitude of 4000 meters from the crater. A half-centered layer of ash covered the villages around the volcano, authorities said. Soldiers and police officers give people a mask.

This time, the shocks caused by volcanic activity are much less than in September, but the head of the Kasbani volcanic center, which, like many Indonesians, uses only the name. Famous for its beaches, lush greenery and Hindu culture, Bali attracted 5 million travelers last year. However, since September, when Agung began to show increased activity, the tourism industry in areas close to the volcano is in crisis.

VOLCANOES IN THE ZONES OF SUBDUCTION

Much more violent and devastating are volcanic eruptions along convergent boundaries where tectonic plates converge. The most volcanically active convergent boundaries are where oceanic plates move beneath continental plates (subduction zones). This is exactly what happens in the Pacific Ring of Fire. In these regions, the magma, due to its chemical composition, is denser than magma at divergent boundaries. Therefore, viscous lava often solidifies underground, forming solid plugs in channels and cracks. Lava, locked under such a cork, continues to emit gas bubbles, the pressure builds up in it and eventually becomes so high that the lava plug flies out like a cork from a champagne bottle. Sometimes this plug is destroyed by an earthquake, and a volcanic eruption begins.

Indonesia is part of the so-called "circle of fire" that surrounds the Pacific Ocean. This is the contact zone of tectonic plates, which often happens with earthquakes and volcanic eruptions. There are over 130 active volcanoes in Indonesia. Therefore, this time we invite you to get acquainted with extremely beautiful, but at the same time very dangerous natural objects - volcanoes.

Bromine is still functional and very dangerous volcano in Indonesian national park Brom-Tenger-Semer. Low plains Segara Vedi, the nearby Semmer volcano, are next to each other with exploding smoke every 20 minutes, and Bromus make them spectacular, giving them an impressive look.

MOUNTAIN ST HELENS

On March 21, 1980, after 123 years of inactivity, earthquakes began around Mount St. Helens in Washington state. On the northern slope, a dome of magma appeared, trapped in a volcano's crater. It grew at a rate of 1.5 m per day. Then, on May 18, 1980, a 5.1 earthquake caused this dome to break off and slide downhill. The pressure holding back the magma beneath him vanished. A massive landslide followed with a rockfall, accompanied by strong outbursts of pumice and ash. Down the slope of the volcano, no less than 17 pyroclastic emissions rushed - clouds of ash, stones and gas with a temperature of more than 1500 ° C. The speed of the streams exceeded 100 km per hour. A powerful explosion blew down the top of the mountain with a height of more than 400 m.

Thousands of life-giving volcanoes

Small mountain Brom is considered sacred - even its name comes from Brahma, the name of an Indian god. The most active volcano in the Philippines is Mayon, and it is active on Luzon Island in the Bicol region. It is well known not only for its almost perfect symmetrical cone shape, but also for its steep upper slopes and extremely dangerous eruptions.

Although courageous people from all over the world see Mayon, their visits are often limited due to the possibility of a threatening giant appearing. Kilimanjaro is a volcanic massif located in East Africa, Tanzania, and consists of three cones: Kibo, Mawenzi and Shiro.

WHAT ARE VOLCANOES DANGEROUS

The dangers posed by volcanoes are very diverse. Volcanic eruptions destroy homes, burn crops, destroy livestock and kill people. However, fertile soils, fertilized with volcanic ash, attract people again and again, and they persistently populate the slopes of volcanoes. For example, the extremely densely populated slopes of the Soufriere volcano on the Caribbean island of Montserrat were completely devastated by the volcanic eruption in 1997.

Ernest Hemingway, who described his volcanic eruption at 5.8 kilometers, promoted him as a mountaineer climber. So it’s not surprising that every year about 35 thousand people want to climb into beautiful beauty and giant clothes with ice. tourists. And the best news for them is that the clamp is not complicated, it does not require any special technique, just for human strength and endurance.

The top offers a beautiful view of the bottom of swampy volcanoes and the sloping forest and horizons. Fuji or Mount Fuji, whose name comes from the word "Fuchi", means "fire" - the national cultural symbol of Japan, which has been worshiped since ancient times. He stumbled upon the island of Honshu, on the Pacific coast, and is only 97 km from Tokyo.

PYROCLASTIC EMISSIONS

The most formidable factor in eruptions is pyroclastic emissions, consisting of hot, suffocating ash, poisonous gases and huge flying stones. Scattering at speeds of up to 300 km per hour, they can envelop areas of many square kilometers. The most famous pyroclastic ejection in history occurred during the eruption of Vesuvius in southern Italy in 79. An avalanche of hot ash and poisonous gases killed many residents of the cities of Pompeii and Herculaneum.

Although the volcano has been calm for over 300 years, geologists consider it active, but not for artists who constantly travel here to capture an icon of Japan. At the bottom of the mountain is the notorious Aokigagar forest, where it perishes every year a large number of of people.

An active volcano celebrated by winter sports enthusiasts

Ruapehu is one of the most active in the world and the most a large volcano in New Zealand, in the Taupo volcanic region. Its eruptions are repeated every 50 years, although there are even 2 ski resort... Ruape was visited not only by thousands of travelers, cyclists and skiers, but also by the trilogy of the Flower Master trilogy, as all three parts of the film were filmed here. The volcano is also popular at the top of the lake's hill, which occurs during the calm period between eruptions.

VOLCANIC POLLUTION

With large volcanic eruptions there is another problem related. They emit so much matter into the atmosphere that they have an impact on the climate. About 74,000 years ago, the eruption of the Toba volcano in Sumatra threw so much volcanic material into the air that chemical composition the atmosphere changed and a cold snap set in on the Earth.

The northern sparkling Icelandic sky appears almost every winter night if only the sky is visible. Sometimes they are barely noticeable and blurred, but sometimes - the image simply suppresses the smell, wants to scream and jump with happiness. It is difficult to understand and imagine those who did not see the living, what is happening at that time in the Icelandic sky. Even a few colors move and mix among themselves, flying through the sky from one edge to the other, as if it were a wind shear belt that shows it, it grows and merges with the sky again.

Sometimes it looks like a curtain with several doves with a lot of swirls in them. The northern garbage is never the same, it differs in shape, brightness and color. The eruption of ghosts in Iceland occurs on average every 3 years. This tragedy of nature can be challenging to travel, but you will not forget such images and feelings of experience throughout your life.

ASH CLOUDS, MUD FLOWS AND FLOODING

Side effects of volcanic eruptions can be no less dangerous. In 1985, a cloud of hot ash from the small volcano Nevado del Ruiz in Colombia melted snow and ice around the summit. Streams of melt water mixed with ash poured down the slopes of the mountain, destroyed a small town and killed more than 20,000 people. The eruption of the Grimsvötn volcano in Iceland in 1996 led to a colossal flood (called "jökülhaup"), in which water erupted at a speed of 50,000 cubic meters per second.

Geysers and geothermal zones

If a volcanic eruption fails to see the living, you will undoubtedly be able to see lava fields, tunnels and craters. Geysers form in only a few parts of the world, so it is important that they arrive in Iceland. They absorb their power, take away the promise and make them fall in love - this is a wonderful phenomenon!

Hot springs of rivers and basins

A river or hot water pool is common in Iceland. Water moving from earth to earth absorbs the properties of the earth's minerals and is therefore beneficial for human skin and health. The Vatnajokull glacier is not only the largest in Iceland, but throughout Europe. This glacier is 1 km thick and occupies almost 8% of the total area of ​​Iceland. The glacier is constantly melting, shrinking and liquefying. You can order a guide and take a safe walk on the ice.

WHAT ARE VOLCANOES USEFUL

Volcanic activity is not always harmful. In Iceland, geothermal heat from underground magma is used to generate electricity and to heat greenhouses that grow food that would otherwise have to be imported. The soils formed during the weathering of lava are very rich in minerals and are extremely fertile when cultivated.

PREDICTION OF ERUPTIONS

To avoid disasters, it is very important to learn how to predict the timing of volcanic eruptions and the estimated strength of the eruption. While it is often easy to recognize early warning signs of an impending eruption, scientists cannot yet predict exactly when the eruption will begin or in which direction the lava and ash will flow. The eruption of volcanoes depends on many geological factors, many of which are not yet fully understood or observable. Continuous monitoring of seismic activity and volcanic gases helps to decipher the first warning signs, however, it seems that accurate prediction of volcanic eruptions will be possible only in the distant future.

In 79 A.D. during the eruption of Mount Vesuvius, a huge cloud of hot ash and gas was thrown out, which buried the ancient Roman city of Pompeii. The burnt bodies left cavities in ash. Subsequently, these cavities were filled with cement.

All three active volcanoes are active, and geologists knew about the approaching eruption. Preheating the summit Klyuchevskoy Sopka(another name for the Klyuchevsky volcano) was visible even from the satellite, and Villarrica is considered the most active volcano in Chile.

There are no large peaks near all three settlements, they are constantly monitored, so even in the event of a large-scale eruption, catastrophic consequences cannot be expected. But some other volcanoes really pose a serious threat.

Why are volcanoes dangerous and why?

The severity of the consequences of an eruption is determined by several factors at once. First, the location is important: Erebus, located in Antarctica, threatens only the Antarctic McMurdo station (up to a thousand people in the summer season), but from Vesuvius to the millionth Naples, only 15 kilometers. The Italian volcano is to blame not only for the destruction of the ancient Roman years of Pompeii and Stabia: in the last century (by geological standards, quite recently), it burned two villages at its foot.

Karl Bryullov, "The Last Day of Pompeii", 1833

Secondly, the type of volcano and the nature of the eruption are important. Eruptions Hawaiian type(so named because it is on the Hawaiian Islands that they are most often found) lead to the emergence of a large volume of lava to the surface, but explosions with scattering of stone fragments and ash clouds usually do not occur. Lava can spread for tens of kilometers, flood settlements, but you can manage to get away from it on foot. In some places, tourists even calmly approach lava flows.

Eruptions of the Plinian type (first described by the ancient Roman writer Pliny the Elder) of the type are much more dangerous, since the top of the volcano literally explodes, throwing out a red-hot stream of ash and gases. The stream, heated to colossal temperatures and rushing with great speed, leaves no chance of survival for those who find themselves in its path. It was these flows, called pyroclastic, that caused the death of the inhabitants of Pompeii, and also accompanied one of the most destructive eruptions - the eruption of the Krakatoa volcano in 1883.


Modern snapshot of Pompeii. The mountain in the background is Vesuvius. Photo: Morn the Gorn / Wikimedia

Ash thrown into the upper layers of the troposphere and stratosphere is dangerous for aircraft (there are known cases of engine failure due to ash), and in large quantities may even lead to a temporary cooling of the entire planet. The eruption of the Icelandic volcano Eyjafjallajökull paralyzed air traffic for almost a week not only in Iceland, but also in the UK, as well as in Northern Europe.

The third factor that determines the danger of an eruption is the volume of ejected material, lava and ash. Everything is simple with him: the more, the worse. There is an international VEI scale, and it, like the magnitude of earthquakes, is of a logarithmic nature, that is, each next step assumes a ten times larger volume.


The beginning of the eruption of Eyjafjallajökull in 2010. Photo: Boaworm / Wikimedia

Considering all this data, there are five volcanoes that are really worth fearing for the inhabitants of planet Earth. Let us emphasize a certain conventionality of this list. For example, it does not coincide with the list of 17 Decade Volcanoes, which was compiled by volcanologists as a list of potentially dangerous fire-breathing mountains requiring additional research. Whether a dormant supervolcano is more dangerous than an active ordinary volcano is a difficult question. We'll start with supervolcanoes.

Yellowstone, supervolcano, USA

The 50-kilometer-long caldera (depression, essentially a giant crater) located in the Rocky Mountains in the United States is the crater of a now inactive volcano. 2.1 million years ago, the volcano ejected 2,500 cubic kilometers of ash and lava. This is enough to cover the territory of an average-sized state with a layer of tens of meters. It is still unknown how the super-eruption affected the flora and fauna of the Earth, but today it would lead to the destruction of settlements within a radius of many hundreds of kilometers, cover most of the United States and Canada with ash, and also cause a global crop failure on the entire planet. due to a cold snap of several degrees.

Since then, there have been two more catastrophic eruptions. Geologists estimate the likelihood of a recurrence at about one and a half ten-thousandths of a percent per year.


It looks like a normal mountain landscape, but in fact the mountains behind are the edge of the volcanic crater from which the picture was taken. Photo: Ed Austin / Herb Jones

Toba, supervolcano, Indonesia

It is his "work" that is associated with a sharp decline in the number of people about 70 thousand years ago. In scale, the eruption is close to that described above: about 2800 cubic kilometers of magma, significant destruction in a radius of over a thousand kilometers, a year or even several years of global cooling.

The current status of Toba is dormant volcano, however, it is located in a seismically dangerous area, and the northern slope of the caldera in one place is devoid of vegetation cover - scientists do not exclude that this is the consequence of a small, and moreover, relatively recent, eruption.


The entire caldera with Lake Toba located inside is visible only from the satellite. Image: NASA Landsat

Santorini, volcano, Crete

This volcano in the Mediterranean destroyed the civilization of ancient Crete (the Aegeans) in 1645-1640 BC. In the documented history of mankind, this is the only case of an eruption that scored seven points on the VEI scale (eight are already supervolcanoes), and Santorini is active volcano. The last eruption occurred in 1950, and in 2011 and 2012, sensors installed by scientists recorded a suspicious deformation of the surface - perhaps magma was accumulating under the volcano again. This may indicate imminent eruption however, it is impossible to accurately assess the risks and magnitude.


Caldera Santorini. The scale can be estimated from the airport runway visible to the right. Image: NASA

Krakatoa, Indonesia

After an explosive eruption in 1883, a submerged crater formed on the site of Mount Krakatoa. The height of the tsunami in the Indian Ocean and the Java Sea reached thirty meters, and the wave destroyed thousands of settlements: the total number of victims exceeded one hundred thousand people. The power of the explosion is estimated by different scientists with a wide scatter, but even according to conservative estimates, it exceeded the figure of the "Tsar Bomba" - the most powerful thermonuclear charge in the history of mankind (it was created in the USSR and detonated on Novaya Zemlya in 1961, the explosion power in TNT equivalent over 50 megatons, which is 2,700 times more than the power of the "Kid", which destroyed Hiroshima).

Now on the site of Krakatoa is literally growing new volcano, Anak (Child) Krakatoa. The cone appeared above the surface of the water at the beginning of the last century, continuous eruptions practically do not stop, and every week the mountain becomes higher by about 13 centimeters.


Piece coral reef, which was torn off and thrown out by the tsunami after the eruption of Krakatoa. Photo from the archive of the Tropenmuseum of the Royal Tropical Institute (KIT), 1885

Lucky, Iceland

This volcano is known for its eruption in 1783-1784. It was not accompanied by a destructive explosion, but it lasted for almost ten months. During this time, about 15 cubic kilometers of lava came to the surface. Poisonous gases released from it and associated ash emissions killed half of all livestock in Iceland, and particles that rose into the stratosphere led to a cold snap throughout Europe. True, since then there have been no new eruptions.


Lucky these days. Photo: Chmee2 / Valtameri / Wikimedia



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