Volcanoes are geological formations on the Earth's surface where magma comes out in the form of lava. These mountains are not only on Earth, but also on other planets. So, the Olympus volcano on Mars reaches a height of several tens of kilometers. Such formations are dangerous not only with lava, but also with the release of a large amount of dust and ash into the atmosphere.
The eruption of the Icelandic volcano Eyjafjallajökull in 2010 made a lot of noise. Although it was not the most destructive in terms of strength, its proximity to Europe led to the impact of emissions on the transport system of the mainland. However, history knows many other cases of the destructive effects of volcanoes. Let's talk about the ten most famous and large-scale of them.
Vesuvius, Italy. On August 24, 79, the volcano Vesuvius erupted, which destroyed not only the well-known city of Pompeii, but also the cities of Stabiae and Herculaneum. Ashes even reached Egypt and Syria. It would be a mistake to assume that the catastrophe destroyed Pompeii alive, out of 20 thousand people, only 2 thousand died. Among the victims was the famous scientist Pliny the Elder, who approached the volcano on a ship in order to explore it and thus found himself practically at the epicenter of the disaster. During the excavations of Pompeii, it was found that under a multi-meter layer of ash, the life of the city froze at the time of the disaster - objects, houses with furnishings remained in their places, people and animals were found. Today, Vesuvius remains the only active volcano on the continental part of Europe, more than 80 of its eruptions are known in total, the very first one supposedly happened 9 thousand years ago, and the last one took place in 1944. Then the cities of Massa and San Sebastiano were destroyed, and 57 people died. Naples is located 15 kilometers from Vesuvius, the height of the mountain is 1281 meters.
Tambora, Sumbawa Island. The cataclysm on this Indonesian island happened on April 5, 1815. This is the largest eruption in modern history in terms of the number of people killed and the volume of ejected material. The catastrophe associated with the eruption and the ensuing famine killed 92,000 people. In addition, the Tambora culture, which Europeans had only met shortly before, completely disappeared from the face of the earth. The volcano lived for 10 days, decreasing during this time in height by 1400 meters. Ashes for 3 days hid the territory within a radius of 500 kilometers from the sun. According to the testimony of the British authorities in those days in Indonesia, it was impossible to see anything at arm's length. Most of the island of Sumbawa was covered with a meter layer of ash, under the weight of which even stone houses crumbled. 150-180 cubic kilometers of gases and pyroclassics were thrown into the atmosphere. The volcano therefore had a strong impact on the climate of the entire planet - ash clouds poorly transmitted the rays of the Sun, which led to a noticeable decrease in temperature. 1816 became known as "the year without summer", in Europe and America the snow melted only in June, and the first frosts appeared already in August. The result was massive crop failures and famine.
Taupo, New Zealand. 27 thousand years ago, a strong volcanic eruption occurred on one of the islands, surpassing even Tamboru in strength. Geologists consider this cataclysm the last such force in the history of the planet. As a result of the work of the supervolcano, Lake Taupo was formed, which today is the object of attention of tourists, as it is very beautiful. The last eruption of the giant took place in 180 AD. The ash and the blast destroyed half of all life on the North Island, about 100 cubic kilometers of tectonic matter fell into the atmosphere. The speed of the rock eruption was 700 km/h. The ash that rose into the sky painted sunsets and sunrises all over the world with purple, which was reflected in the ancient Roman and Chinese chronicles.
Krakatau, Indonesia. The volcano, located between the islands of Sumatra and Java, produced on August 27, 1883 the largest explosion of its kind in modern history. During the cataclysm, a tsunami up to 30 meters high appeared, which simply washed away 295 villages and cities, while about 37 thousand people died. The roar from the explosion was heard on 8% of the entire surface of the planet, and pieces of lava were thrown into the air to an unprecedented height of 55 kilometers. The wind carried the volcanic ash so much that after 10 days it was found at a distance of 5330 kilometers from the scene. The mountain-island then split into 3 small parts. The wave from the explosion circled the earth from 7 to 11 times, geologists believe that the explosion was 200 thousand times stronger than the nuclear strike on Hiroshima. Krakatau woke up before, so, in 535, his activity significantly changed the climate of the planet, perhaps then the islands of Java and Sumatra were divided. On the site of the volcano destroyed in 1883 during an underwater eruption in 1927, a new volcano, Anak Krakatau, appeared, which is still quite active today. Its height is now 300 meters due to new activities.
Santorini, Greece. Approximately one and a half thousand years BC, a volcanic eruption occurred on the island of Thera, which put an end to the entire Cretan civilization. Sulfur covered all the fields, which made further farming unthinkable. According to some versions, it is Thera that is the very Atlantis described by Plato. Someone also believes that the eruption of Santorini entered the annals, like a pillar of fire seen by Moses, and the parted sea is nothing more than the consequences of the disappearance of the island of Thera under water. However, the Volcano continued its activity, in 1886 its eruption lasted a whole year, while pieces of lava flew straight out of the sea and rose to a height of 500 meters. As a result - several new islands nearby.
Etna, Sicily. About 200 eruptions of this Italian volcano are known. Among them were quite powerful ones, so, in 1169, about 15 thousand people died during the cataclysm. Today, Etna remains an active volcano with a height of 3329 meters, waking up about once every 150 years and destroying one of the nearby villages. Why don't people leave the slopes of the mountain? The fact is that the frozen lava helps the soil to become more fertile, which is why the Sicilians settle here. In 1928, besides, a miracle happened - the flow of red-hot lava stopped in front of the Catholic procession. This inspired the believers so much that in 1930 a chapel was erected on this site, 30 years later the lava stopped in front of it. The Italians protect these places, so in 1981 the local government created a reserve around Etna. It is curious that a blues music festival is even arranged on a calm volcano. Etna is quite large, exceeding the size of Vesuvius by 2.5 times. The volcano has from 200 to 400 side craters, lava erupts from one of them every three months.
Montagne Pele, Martinique island. The volcanic eruption on the island began in April 1902, and on May 8 a whole cloud of vapors, gases and red-hot lava hit the city of Saint-Pierre, located 8 kilometers away. A few minutes later he was gone, and of the 17 ships that were in the harbor at that moment, only one managed to survive. The ship "Roddam" escaped from the clutches of the elements with broken masts, smoking and littered with ash. Of the 28 thousand inhabitants of the city, two escaped, one of them was called Opost Siparis, and he was sentenced to death. He was saved by the thick stone walls of the prison. Subsequently, the prisoner was pardoned by the governor, spending the rest of his life traveling the world with stories about what happened. The force of the blow was such that the monument on the square, weighing several tons, was thrown aside, and the heat was such that even the bottles melted. It is interesting that the outpouring of liquid lava did not directly occur, the impact was caused by vapors, gases and pulverized lava. Later, a sharp lava plug 375 meters high came out of the crater of the volcano. It also turned out that the bottom of the sea near Martinique had sunk several hundred meters. The city of Saint-Pierre, by the way, became famous for the birth of Napoleon's wife, Josephine Beauharnais, in it.
Nevado del Ruiz, Colombia. A volcano 5400 meters high, located in the Andes, splashed out lava flows on November 13, 1985, and the main blow fell on the city of Armero, located 50 kilometers away. It took only 10 minutes for the lava to destroy it. The death toll exceeded 21 thousand people, and in total at that time about 29 thousand lived in Armero. Sadly, no one listened to the volcanologists' information about the impending eruption, since the specialists' information was repeatedly not confirmed.
Pinatubo, Philippines. Until June 12, 1991, the volcano was considered extinct for 611 years. The first signs of activity appeared in April and the Philippine authorities managed to evacuate all residents within a radius of 20 kilometers. The eruption itself claimed the lives of 875 people, while the US naval base and the US strategic air base, located 18 kilometers from Pinatubo, were destroyed. The ejected ash covered an area of 125,000 km2 of the sky. The consequences of the disaster were a general decrease in temperature by half a degree and a reduction in the ozone layer, due to which a very large ozone hole formed over Antarctica. The height of the volcano before the eruption was 1486 meters, and after - 1745 meters. At the site of Pinatubo, a crater with a diameter of 2.5 kilometers was formed. Today, earthquakes regularly occur in this area, preventing any construction within a radius of tens of kilometers.
Katmai, Alaska. The eruption of this volcano on June 6, 1912 was one of the largest in the 20th century. The height of the ash column was 20 kilometers, and the sound reached the capital of Alaska, the city of Juneau, located 1200 kilometers away. At a distance of 4 kilometers from the epicenter, the ash layer reached 20 meters. Summer in Alaska turned out to be very cold, as the rays could not break through the cloud. After all, thirty billion tons of rocks were taken into the air! In the crater itself, a lake with a diameter of 1.5 kilometers formed, and it became the main attraction of the Katmai National Park and Reserve formed here in 1980. Today, the height of this active volcano is 2047 meters, and the last known eruption occurred in 1921.
Most of the volcanoes on our planet are located in the "ring of fire", which stretches along the shores of the entire Pacific Ocean. And in total there are about 1.5 thousand volcanoes on Earth, of which 540 are active.
Here is a list of the most dangerous ones.
1. Nyiragongo, height 3470 m, Democratic Republic of the Congo
This is one of the most dangerous volcanoes in Africa. Since 1882, 34 eruptions have been recorded here. The main crater is 250 meters deep and 2 km wide, and contains a lake of actively bubbling lava. This lava is unusually fluid and its flows can reach speeds of 100 km/h. In 2002, the eruption killed 147 people and left 120,000 homeless. The last eruption to date occurred in 2016.
2. Taal, height 311 m, Philippines
This is one of the smallest active volcanoes on our planet. It has erupted 34 times since 1572. Located on the island of Luzon, on Lake Taal. The strongest eruption of this volcano in the 20th century occurred in 1911 - 1335 people died in 10 minutes and in general all living things at a distance of up to 10 km. In 1965, 200 people died. Last eruption - 1977
3. Mauna Loa, height 4169 m, Hawaii (USA)
There are many volcanoes in Hawaii, but this is the largest and most dangerous of all. Since 1832, 39 eruptions have been recorded. The last eruption occurred in 1984, the last strong eruption in 1950.
4. Vesuvius, height 1281 m, Italy
One of the most dangerous volcanoes in the world is located just 15 km east of Naples. The most famous historical eruption occurred in 79 AD. As a result of this catastrophe, two cities - Pompeii and Herculaneum - disappeared from the face of the Earth. In modern history, the last eruption of Vesuvius happened in 1944.
5. Merapi, height 2,930 m, Indonesia
This most active active volcano in Indonesia is located on the island of Java near the city of Yogyakarta. "Merapi" is translated as "mountain of fire". The volcano is young, so it puffs with enviable regularity. Large eruptions occur on average every 7 years. In 1930, about 1300 people died, in 1974 two villages were destroyed, in 2010 353 people died. Last eruption - 2011
6. St. Helens, height 2,550 m, USA
Located 154 km from Seattle and 85 km from Portland. The most famous eruption of this active volcano occurred in 1980, when 57 people died. The eruption was of a rare type - "directed explosion". The process of the volcanic eruption and the spread of the ash cloud was photographed by photographer Robert Landsburg, who died during this eruption, but kept the film. The last activity to date was recorded in 2008.
7. Etna, height 3,350 m, Italy
Mount Etna is located on the east coast of Sicily. It is the highest active volcano in Europe. During its existence, it erupted about 200 times. In 1992, one of the largest eruptions was recorded, during which the town of Zafferana barely escaped. On December 3, 2015, the central crater of the volcano threw a fountain of lava to a kilometer high. The last eruption is February 27, 2017.
8. Sakurajima, height 1117 m, Japan
The volcano is located on the Osumi Peninsula of Kyushu Island in the Japanese prefecture of Kagoshima. There is almost always a cloud of smoke above the volcano. The eruptions were recorded on August 18, 2013, in March 2009. The last eruption was recorded on July 26, 2016.
9. Galeras, height 4276 m, Colombia
Over the past 7 thousand years, at least six large eruptions and many small ones have occurred on Galeras. In 1993, during research work in the crater, six volcanologists and three tourists died (then the eruption also began). Latest recorded eruptions: January 2008, February 2009, January and August 2010
10. Popocatepetl, height 5426 m, Mexico
The name translates as "smoking hill". The volcano is located near Mexico City. It has erupted 20 times since 1519. The last eruption was recorded in 2015.
11. Unzen, height 1,500 m, Japan
The volcano is located on the Shimabara Peninsula. The eruption of Mount Unzen in 1792 is one of the five most destructive eruptions in human history in terms of the number of human casualties. The eruption caused a tsunami 55 meters high, which killed more than 15 thousand people. And in 1991, 43 people died during the eruption. No eruptions have been observed since 1996.
12. Krakatoa, height 813 m, Indonesia 
This active volcano is located between the islands of Java and Sumatra. Before the historic eruption of 1883, the volcano was much higher and was one large island. However, the most powerful eruption of 1883 destroyed the island and the volcano. Today, Krakatau is still active and small eruptions occur fairly regularly. Last activity - 2014.
13. Santa Maria, height 3,772 m, Guatemala
The first recorded eruption of this volcano occurred in October 1902, before that he "rested" for 500 years. The explosion was heard 800 km away in Costa Rica, and the ash column rose 28 km. About 6 thousand people died. Today the volcano is active. The last eruption was recorded in 2011.
14. Klyuchevskaya Sopka, height 4835 m, Russia
The volcano is located in the east of Kamchatka, 60 km from the coast. It is the largest active volcano in Russia. Over the past 270 years, more than 50 eruptions have been recorded, the last in April 2016.
15. Karymskaya Sopka, height 1468 m, Russia
Also located in Kamchatka. More than 20 eruptions have been recorded since 1852. Eruptions of recent years: 2005, 2010, 2011, 2013, 2014, 2015 A very restless volcano.
19.02.2014
In countries where there are volcanoes, such as Indonesia, they are located in such large provinces as West Java, East Java or Central Java. One of the most terrible disasters is a volcanic eruption, which can claim hundreds or even thousands of lives. It is impossible to forget about the eruption of the Krakatau volcano, the huge damage and thousands of victims. And here we present a list of the most dangerous and active volcanoes in the world. However, not all volcanoes are dangerous. is in great demand among travelers and connoisseurs of wildlife.
No. 10. Hawaii, Mauna Loa volcano
Mauna Loa is one of the five mountains that make up the island of Hawaii. Despite the fact that it is not the highest mountain, the volcanic eruption poses a high danger, since its lava is basically a liquid, which can lead to serious fires. Mauna LOA is the largest volcano in the world (in terms of volume and area), with the volume of lava, it reaches 18,000 cubic miles. The last eruption occurred on April 15, 1984.
No. 9. Philippines, Taal volcano
Approximately 50 km (31 miles) from the capital city of Manila, one of the most dangerous volcanoes, Taal. This mountain is an island in Taal Lake, which is located inside a caldera formed as a result of very strong previous eruptions (this process is similar to Lake Toba). Taal Volcano is a complex of volcanoes on the island of Luzon in the Philippines. This volcano has erupted several times, including one of the most powerful eruptions that claimed more than a thousand people.
No. 8. Papua New Guinea, Ulavun Volcano
Ulawun volcano is located in Papua New Guinea, on the Bismarck archipelago, and is one of the most active and dangerous volcanoes New Guinea. Several eruptions have been recorded, one of the strongest being in 1980, with a plume of ash erupting from Ulawun reaching 60,000 feet in height and its pyroclastic flows engulfing the mountains on all sides.
No. 7. Congo, Nyiragongo Volcano
It has erupted at least 34 times since 1882. One of the worst eruptions occurred on September 17, 2002, when lava that flowed down the slopes of Nyiragongo covered about 40% of the city of Goma and left almost 120,000 people homeless. Nyiragongo is one of most active volcanoes in Africa, its activity never stops.
No. 6. Indonesia, volcano Merapi
Mount Merapi is a conical volcano located in Indonesia on the border between Central Java and Yogyakarta. Much of the Merapi eruption, including the lava, continues to descend, occasionally accompanied by hot smoke capable of spreading at speeds of up to 120 km per hour. This is the most active and dangerous volcanoes in Indonesia, they became active 10,000 years ago, and since 1548 their activity has not stopped.
No. 5. Colombia, Galeras volcano
This mountain most active volcano in Colombia. Since 2000, its eruptions have occurred almost every year. This is dangerous, because the frequency of eruptions is unpredictable. The Galeras volcano has been active for at least a million years. Its location near the southern Colombian border with Ecuador would have caused hot lava to descend down the slope of Mount Galeras for 3.5 km. The latest eruption on January 3, 2010 forced the government to evacuate 8,000 people.
No. 4. Japan, Sakurajima volcano
The Sakurajima volcano is located on the island of Kyushu in Japan and is one of the the most dangerous volcanoes. On March 10, 2009, a terrible eruption occurred, when the volcano threw stones and other rocks up to 2 miles away. The intensity of the Sakurajima eruption is one of the strongest not only in Japan, but also in the world. Over the past 45 years, 73 eruptions have been recorded.
No. 3. Mexico, Popocatepetl volcano
The active volcano Popocatepetl is located at an altitude of 5426 meters above sea level. Beginning in December 1994, the dangerous activity of the volcano continued, until in 2000 there was the most powerful eruption known to history. Since 1519, 20 eruptions have been recorded. The explosion was so strong that it threw ashes over a fairly long distance.
No. 2. Italy, Vesuvius volcano
Mount Vesuvius is an active volcano in the Gulf of Naples, Italy, about 9 miles east of Naples. Mount Vesuvius is the only volcano in Europe that has erupted in the last 100 years. This volcano could explode at any moment and severely punish the people living in its vicinity. A lava eruption from a volcano can reach great heights, so in March 1994 lava splashed up to a height of 1000 meters. The famous eruption of 79 AD destroyed the ancient Roman cities of Pompeii and Herculaneum.
No. 1. USA, Yellowstone Volcano
Volcano Yellowstone - the most dangerous and active volcano in the world. Rocks and rocks ejected from this volcano can fly up to 1000 km. The volcanic eruption of lava and ash from this mountain threatens the extinction of the living and can cause a mass disaster because it will entail other volcanic activities determined by tectonic fluctuations, which will cause other explosions.
Volcanoes on Earth are divided into two types:
- Active(active) - erupted in the historical period of time or during the Holocene (in the last 10 thousand years). Some active volcanoes may be considered sleeping, but eruptions are still possible on them.
- Inactive(extinct) - ancient volcanoes that have lost their activity.
There are about 900 active volcanoes on land (see the list of the largest volcanoes below), in the seas and oceans their number is being specified.
The period of a volcanic eruption can last from several days to several million years.
On other planets
Types of volcanic structures
In general, volcanoes are divided into linear And central, however, this division is conditional, since most volcanoes are confined to linear tectonic faults ( faults) in the earth's crust.
The forms of volcanoes of the central type depend on the composition and viscosity of the magma. Hot and easily mobile basaltic magmas create vast and flat panel board volcanoes (Mauna Loa, Mauna Kea, Kilauea). If the volcano periodically erupts either lava or pyroclastic material, a cone-shaped layered structure, a stratovolcano, arises. The slopes of such a volcano are usually covered with deep radial ravines - barrancos. Volcanoes of the central type can be purely lava, or formed only by volcanic products - volcanic slag, tuffs, etc. formations, or be mixed - stratovolcanoes.
There are also monogenic And polygenic volcanoes. The first arose as a result of a single eruption, the second - multiple eruptions. Viscous, acidic, low-temperature magma, squeezing out of the vent, forms extrusive domes (Montagne-Pele needle, 1902).
- Shield (shield) volcanoes. Formed as a result of repeated ejections of liquid lava. This form is characteristic of volcanoes erupting low-viscosity basaltic lava: it flows for a long time both from the central vent and from the side craters of the volcano. Lava evenly spreads over many kilometers; Gradually, a wide “shield” with gentle edges is formed from these layers. An example is the Mauna Loa volcano in Hawaii, where lava flows directly into the ocean; its height from the foot at the bottom of the ocean is approximately ten kilometers (while the underwater base of the volcano has a length of 120 km and a width of 50 km).
- cinder cones. During the eruption of such volcanoes, large fragments of porous slag pile up around the crater in layers in the form of a cone, and small fragments form sloping slopes at the foot; with each eruption, the volcano gets higher and higher. This is the most common type of volcanoes on land. They are no more than a few hundred meters high. Cinder cones often form as side cones of a large volcano, or as separate centers of eruptive activity during fissure eruptions. An example - several groups of cinder cones appeared during the last eruptions of the Plosky Tolbachik volcano in Kamchatka in 1975-76 and in 2012-2013.
- Stratovolcanoes, or "layered volcanoes". Periodically erupt lava (viscous and thick, quickly solidifying) and pyroclastic substance - a mixture of hot gas, ash and red-hot stones; as a result, deposits on their cone (sharp, with concave slopes) alternate. The lava of such volcanoes also flows out of cracks, solidifying on the slopes in the form of ribbed corridors, which serve as a support for the volcano. Examples are Etna, Vesuvius, Fujiyama.
- dome volcanoes. They are formed when viscous granite magma, rising from the bowels of the volcano, cannot flow down the slopes and freezes at the top, forming a dome. It clogs its mouth, like a cork, which, over time, is kicked out by the gases accumulated under the dome. Such a dome is now forming over the crater of Mount St. Helens in the northwestern United States, formed during the 1980 eruption.
- Complex (mixed, composite) volcanoes.
Volcano Baransky. Iturup Island.
Volcanic eruption
Hawaiian type
Strombolian type
Volcanic eruptions are geological emergencies that often lead to natural disasters. The eruption process can last from several hours to many years.
An eruption is understood as the process of coming from the depths to the surface of a significant amount of incandescent and hot volcanic products in a gaseous, liquid and solid state. During eruptions, volcanic structures are formed - a characteristic form of elevation, confined to channels and cracks, through which eruption products come to the surface from magma chambers. Usually they have the shape of a cone with a recess - a crater at the top. In the event of its subsidence and collapse, a caldera is formed - a vast circus-shaped basin with steep walls and a relatively flat bottom.
The generally accepted assessment of the strength of the eruption, or its explosiveness, without taking into account the individual characteristics of the volcano, is made on the Volcanic Explosivity Index (VEI) scale. It was proposed in 1982 by American scientists C.A. Newhall and S.Self, allowing a general assessment of the eruption in terms of its impact on the earth's atmosphere. An indicator of the strength of a volcanic eruption, regardless of its volume and location, in the VEI scale is the volume of erupted products - tephra and the height of the ash column - an eruptive column.
Among the various classifications, general types of eruptions stand out:
- Hawaiian type- ejections of liquid basalt lava, lava lakes are often formed, the lava flow can spread over long distances.
- Strombolian type- the lava is thicker and is ejected from the vent by frequent explosions. The formation of ash cones, volcanic bombs and lapilli is characteristic.
- plinian type- powerful rare explosions capable of throwing tephra to a height of up to several tens of kilometers.
- Peleian type- eruptions, the hallmark of which is the formation of extrusive domes and pyroclastic flows ("scorching clouds").
- Gas (frheotic) type- eruptions in which only volcanic gases reach the crater and solid rocks are ejected. Magma is not observed.
- Underwater type- eruptions occurring under water. As a rule, they are accompanied by emissions of pumice.
Post-volcanic phenomena
After eruptions, when the activity of the volcano either ceases forever, or it "dozes" for thousands of years, processes associated with the cooling of the magma chamber and called post-volcanic. These include:
During eruptions, sometimes a collapse of a volcanic structure occurs with the formation of a caldera - a large depression with a diameter of up to 16 km and a depth of up to 1000 m. When magma rises, the external pressure weakens, gases and liquid products associated with it break out to the surface, and a volcano erupts. If not magma is brought to the surface, but ancient rocks, and water vapor, formed during the heating of groundwater, predominates among the gases, then such an eruption is called phreatic.
Eiffel Volcanic Domes
Lava that has risen to the earth's surface does not always come out to this surface. It only raises layers of sedimentary rocks and solidifies in the form of a compact body (laccolith), forming a kind of system of low mountains. In Germany, such systems include the Rhön and Eifel regions. On the latter, another post-volcanic phenomenon is observed in the form of lakes that fill the craters of former volcanoes that failed to form a characteristic volcanic cone (the so-called maars).
Geysers are found in areas with volcanic activity, where hot rocks are located close to the surface of the earth. In such places, groundwater is heated to a boiling point, and a fountain of hot water and steam is periodically thrown into the air. In New Zealand and Iceland, geyser and hot spring energy is used to generate electricity. One of the most famous geysers in the world is the Old Faithful Geyser in Yellowstone National Park (USA), which shoots a jet of water and steam every 70 minutes to a height of 45 m.
Mud volcanoes are small volcanoes through which not magma comes to the surface, but liquid mud and gases from the earth's crust. Mud volcanoes are much smaller than ordinary volcanoes. The mud usually comes to the surface cold, but the gases erupted by mud volcanoes often contain methane and can ignite during the eruption, creating a picture similar to a miniature eruption of an ordinary volcano.
Heat sources
One of the unsolved problems of manifestation of volcanic activity is the determination of the heat source necessary for the local melting of the basalt layer or mantle. Such melting must be highly localized, since the passage of seismic waves shows that the crust and upper mantle are usually in a solid state. Moreover, the thermal energy must be sufficient to melt huge volumes of solid material. For example, in the United States in the Columbia River Basin (Washington and Oregon), the volume of basalts is more than 820 thousand km³; similar large strata of basalts are found in Argentina (Patagonia), India (Decan Plateau) and South Africa (Great Karoo Rise). There are currently three hypotheses. Some geologists believe that the melting is due to local high concentrations of radioactive elements, but such concentrations in nature seem unlikely; others suggest that tectonic disturbances in the form of shifts and faults are accompanied by the release of thermal energy. There is another point of view, according to which the upper mantle is in a solid state under conditions of high pressures, and when the pressure drops due to cracking, the so-called phase transition occurs - the solid rocks of the rock mantle melt and liquid lava flows out of the cracks onto the Earth's surface.
extraterrestrial volcanoes
Volcanoes exist not only on Earth, but also on other planets and their satellites. The first highest mountain in the solar system is the Martian volcano Olympus 21.2 km high.
On some satellites of the planets (Enceladus and Triton), at low temperatures, the erupted "magma" does not consist of molten rocks, but of water and light substances. This type of eruptions cannot be attributed to ordinary volcanism, therefore this phenomenon is called cryovolcanism.
Famous eruptions
- The eruption of the Krakatoa volcano in Indonesia in 1883 produced the loudest rumble ever heard in history; the sound was heard at a distance of more than 4800 km from the volcano. Atmospheric shock waves circled the Earth seven times and were still visible for 5 days. The eruption killed more than 36,000 people, destroyed 165 villages and damaged another 132 (mainly through the tsunami that followed the eruption). Volcanic eruptions after 1927 formed a new volcanic island called Anak Krakatoa.
- The Kilauea volcano on the island of Hawaii is the most active volcano at present. The last eruption has been going on since 1983, and lava flows reach the ocean.
- In 2010, the Eyjafjallajökull volcano eruption caused the cancellation of more than 60,000 flights across Europe.
Recent eruptions
Scientists have observed eruptions on 560 volcanoes. The last largest of them are presented in the list:
The largest volcanoes on Earth
The largest areas of volcanic activity are South America, Central America, Java, Melanesia, the Japanese Islands, the Kuril Islands, Kamchatka, the northwestern part of the USA, Alaska, the Hawaiian Islands, the Aleutian Islands, Iceland, etc.
| The name of the volcano | Location | Height, | Region |
|---|---|---|---|
| Ojos del Salado | Chilean Andes | 6893 | South America |
| Llullaillaco | Chilean Andes | 6723 | South America |
| San Pedro | Central Andes | 6159 | South America |
| Cotopaxi | Equatorial Andes | 5911 | South America |
| kilimanjaro | Masai plateau | 5895 | Africa |
| misty | Central Andes (southern Peru) | 5821 | South America |
| Orizaba | Mexican highlands | 5700 | |
| Elbrus | Greater Caucasus | 5642 | Europe |
| popocatepetl | Mexican highlands | 5455 | North and Central America |
| Sangay | Equatorial Andes | 5230 | South America |
| Tolima | Northwestern Andes | 5215 | South America |
| Klyuchevskaya Sopka | peninsula Kamchatka | 4850 | Asia |
| Rainier | Cordillera | 4392 | North and Central America |
| Tahumulco | Central America | 4217 | North and Central America |
| mauna loa | O. Hawaii | 4169 | Oceania |
| Cameroon | Massif Cameroon | 4100 | Africa |
| Erciyes | Anatolian plateau | 3916 | Asia |
| Kerinci | O. Sumatra | 3805 | Asia |
| Erebus | O. Ross | 3794 | Antarctica |
| Fujiyama | O. Honshu | 3776 | Asia |
| Teide | Canary Islands | 3718 | Africa |
| Seven | O. Java | 3676 | Asia |
| Ichinskaya Sopka | peninsula Kamchatka | 3621 | Asia |
| Kronotskaya Sopka | peninsula Kamchatka | 3528 | Asia |
| Koryakskaya Sopka | peninsula Kamchatka | 3456 | Asia |
| Etna | O. Sicily | 3340 | Europe |
| Shiveluch | peninsula Kamchatka | 3283 | Asia |
| Lassen Peak | Cordillera | 3187 | North and Central America |
| Liaima | Southern Andes | 3060 | South America |
| apo | O. Mindanao | 2954 | Asia |
| Ruapehu | New Zealand | 2796 | Australia Oceania |
| paektusan | Korean peninsula | 2750 | Asia |
| Avachinskaya Sopka | peninsula Kamchatka | 2741 | Asia |
| Alaid | Kuril Islands | 2339 | Asia |
| Katmai | Alaska Peninsula | 2047 | North and Central America |
| tyatya | Kuril Islands | 1819 | Asia |
| Haleakala | O. Maui | 1750 | Oceania |
| Hekla | O. Iceland | 1491 | Europe |
| Montagne Pele | O. Martinique | 1397 | North and Central America |
| Vesuvius | Apennine Peninsula | 1277 | Europe |
| Kilauea | O. Hawaii | 1247 | Oceania |
| Stromboli | Aeolian Islands | 926 | Europe |
| Krakatoa | Sunda Strait | 813 | Asia |
The list of the largest eruptions in the history of the Earth is constantly updated as the issue is researched.
In culture
Bryullov K.P. The Last Day of Pompeii. 1830-1833
- Painting by Karl Bryullov “The Last Day of Pompeii”, Russian Museum, St. Petersburg, Russian Federation;
- Movies "Volcano", "Dante's Peak" and a scene from the film "".
- The Eyjafjallajökull volcano in Iceland during its eruption became the hero of a huge number of humorous programs, TV news stories, reports and folk art discussing events in the world.
A truly amazing sight is a volcanic eruption. But what is a volcano? How does a volcano erupt? Why do some of them spew huge lava flows at different intervals, while others sleep peacefully for centuries?
What is a volcano?
Outwardly, the volcano resembles a mountain. There is a geological fault inside it. In science, it is customary to call a volcano a formation of geological rock located on the surface of the earth. Through it, magma erupts outward, which is very hot. It is magma that subsequently forms volcanic gases and stones, as well as lava. Most of the volcanoes on earth formed several centuries ago. Today, new volcanoes occasionally appear on the planet. But this happens much less often than before.
How are volcanoes formed?
Briefly explaining the essence of the formation of a volcano, it will look like this. Under the earth's crust is a special layer under strong pressure, consisting of molten rocks, and it is called magma. If cracks suddenly begin to appear in the earth's crust, then hills form on the surface of the earth. Magma comes out through them under strong pressure. At the surface of the earth, it begins to break up into red-hot lava, which then solidifies, causing the volcanic mountain to become larger and larger. The emerging volcano becomes such a vulnerable spot on the surface that it erupts volcanic gases onto the surface with great frequency.
What is a volcano made of?
In order to understand how magma erupts, you need to know what the volcano consists of. Its main components are: volcanic chamber, vent and craters. What is the focus of a volcano? This is where magma forms. But not everyone knows what the mouth and crater of a volcano are? A vent is a special channel that connects the hearth with the surface of the earth. A crater is a small bowl-shaped depression on the surface of a volcano. Its size can reach several kilometers.
What is a volcanic eruption?
Magma is constantly under strong pressure. Therefore, there is a cloud of gases above it at any time. Gradually, they push the red-hot magma to the surface of the earth through the mouth of the volcano. That's what causes the eruption. However, one small description of the eruption process is not enough. To see this spectacle, you can use the video, which you need to watch after you have learned what the volcano consists of. In the same way, in the video you can find out which volcanoes do not exist at the present time and what volcanoes that are active today look like.
Why are volcanoes dangerous?
Active volcanoes are dangerous for a number of reasons. By itself, a dormant volcano is very dangerous. He can “wake up” at any time and start spewing lava flows that spread over many kilometers. Therefore, you should not settle near such volcanoes. If an erupting volcano is located on the island, such a dangerous phenomenon as tsunami may occur.
Despite their danger, volcanoes can serve mankind well.
Why are volcanoes useful?
- During the eruption, a large number of metals appear that can be used in industry.
- The volcano generates the strongest rocks that can be used for construction.
- Pumice, which appears as a result of the eruption, is used for industrial purposes, as well as in the production of stationery gum and toothpaste.
