Dormant volcanoes awaken around the world

The structure of the earth is directly related not only to tectonic earthquakes, but also to volcanic eruptions, often accompanied by significant earthquakes. Earthquakes that occur during volcanic eruptions are so frequent that almost all people are sure that volcanoes are the cause of earthquakes. This was the opinion of ancient Greek philosophers who studied the widespread occurrence of earthquakes and volcanoes in the Mediterranean. A small island still exists in the Tyrrhenian Sea in the group of Aeolian Islands. The name of this island is Vulcano. The ancient Greeks saw clouds of black smoke, columns of fire, and hot stones thrown to great heights from the top of the mountain, which occupied a large area of ​​the island. This island was considered by the Greeks and Romans to be the entrance to hell and the possession of the god of fire and blacksmithing, Vulcan. Today, seismologists classify volcanic earthquakes as a special group, since volcanic eruptions are not always accompanied by an earthquake. All volcanoes are divided into two groups - active, dying or dormant and extinct. But scientists themselves consider this gradation to be very shaky and relative.

Extinct and dormant volcanoes

Extinct volcanoes are volcanoes that erupted in times long past, and about whose activity there is simply no information preserved. On Earth, the number of extinct volcanoes is much greater than the number of active and dying ones. Some of the extinct ones were active in the recent past, others ended their lives in more distant times. Some of them have retained the shape of a regular cone, just like most volcanoes usually have a cone shape with gentle slopes at the base and steeper slopes at the tops. The top of such a cone is crowned by a deep depression with steep walls, creating an abyss shaped like a giant bowl. Due to its similarity to a bowl, the volcano’s cavity was called a crater. Сrater is a Latin term borrowed by the ancient Romans from the ancient Greek word for “mix.” Thus, the word "krater" is translated as an ancient vessel for mixing wine with water. Since the ancients did not drink pure wine, considering such drinking to be the lot of barbarians and slaves, and always diluted it with water, when constantly drinking diluted wine instead of juice, they needed large bowls for mixing wine with water. In short, a volcanic crater is a bowl-shaped depression on the top or slope of a volcanic cone.

Currently, there are volcanoes whose activity can be described as “decaying”. These volcanoes help to understand the processes that occurred with extinct volcanoes. Since volcanism is a dynamic phenomenon, then, therefore, like any dynamics, volcanism has a beginning, development and ending in its existence. All volcanoes change after their emergence and undergo a number of transformations. They either “fall asleep”, collapsing, then “wake up” again, smoking, but they live only as long as there is a sufficient amount of volcanic energy in their underground foci. With a decrease in energy, the activity of the volcano begins to lose dynamics and dies. The volcano fades and falls asleep. And even during the period of falling asleep, jets of gases and water vapor can be released from the crater, which, settling on the walls of the crater, often form rocks, mostly clayey or alunite. When the energy is completely exhausted, the volcano stops all activity, its active life. The volcano is extinct.

In our country, the remains of ancient volcanoes can be seen in the Caucasus, Crimea, Transbaikalia, Kamchatka and other places. However, local earthquakes sometimes occur under extinct volcanoes, indicating that at any moment these volcanoes can “wake up” and become active. Such extinct, but suddenly awakened volcanoes include the Bezymianny and Academy of Sciences volcanoes in Kamchatka. Nameless woke up in 1956, the Academy of Sciences - in 1997. Volcano St. Helens in the USA (1980) is also among those who have awakened. These volcanoes were considered long extinct, and their awakening was unexpected and powerful. It was marked powerful eruption huge amount volcanic formations. After the awakening of Mount St. Helens, the US Geological Survey established observations of 16 “sleeping” volcanoes in the states of Washington, California, Hawaii, and Alaska. In addition, by collaborating with scientists from Iceland and Latin America, the Americans established observations of extinct volcanoes in Iceland, Guatemala, El Salvador, Nicaragua and Ecuador. On the territory of Russia, active and potentially active (“dormant”) include numerous volcanoes of the Kuril-Kamchatka island arc, as well as volcanoes of the Elbrus and Kazbek groups.

The peaks of Kazbek and Elbrus are covered with sparkling eternal snow and glaciers. Volcanologists are constantly monitoring the extinct volcanoes of the Greater Caucasus, especially after an unexpected awakening Kamchatka volcano Nameless. But the volcanic activity of, for example, Elbrus leaves no doubt: from the crater Eastern peak(5621 meters) gases constantly ooze; at the foot of the mountain, at a distance of several tens of kilometers, so-called “mineral” waters gush out, that is, waters saturated with gases and mineral salts, the origin of which is undoubtedly related to saturation groundwater evaporations of gases from boiling magma, such as the well-known Narzan or Essentuki.

Elbrus Volcano is such a powerful natural structure that its eruption can only be catastrophic. If it happens, it will be felt not only by residents of the Caucasus, Crimea, Stavropol and Krasnodar territories, but also by Ukraine, all of Europe, and Asia. The proportions of Elbrus speak for themselves: the height of the Western peak is 5642 meters, the Eastern peak is 5621 meters, the saddle between the peaks is at an altitude of 5416 meters. The diameter of the base of Elbrus is about 18 kilometers. This is a young volcano of the Caucasus. It can be classified as an active but dormant volcano. The huge mountain is covered with a hundred-meter-high ice shell; glaciers flow from the top, feeding the rivers of the Kuban, Malki, and Baksan basins. Here the weather can change in a matter of minutes. In the heat of August at the top of Elbrus it is -20 degrees and there is always a strong wind. The oxygen content is reduced, and this fact requires preliminary preparation and acclimatization to prevent altitude sickness.

The volcanoes of Kamchatka are also constantly monitored by scientific volcanologists, who have branched off from scientific geologists and the science of geology into a separate independent subject of science: volcanology. The observation is carried out on the basis of a volcanological observatory station located in Kamchatka near Petropavlovsk-Kamchatsky in the village of Klyuchi, on the slope of the Avacha volcano, which is located at the very foot of the Klyuchevsky volcano. Despite the fact that it is dangerous to live in the vicinity of volcanoes, villages and even cities almost always grow there. Such are Naples near Vesuvius, Petropavlovsk-Kamchatsky in the zone of the Kuril-Kamchatka hills, cities and villages of Sicily, constantly suffering from the eruption of Mount Etna, and many, many others...

The study of extinct and dormant volcanoes helps to understand how molten masses and magmas penetrate into the solid crust of the earth and what happens from the contact of magma with rocks. As one would expect, chemical processes usually occurred at the places where magma contacted rocks, resulting in the formation of mineral ores - deposits of iron, copper, zinc and other metals. In addition, the jets of water vapor and volcanic gases escaping from the crater carry some chemicals with them to the surface in a dissolved and gaseous state. Therefore, in the cracks of the crater and near it, deposits of sulfur, ammonia, and boric acid are found, which are always necessary in industry. How can we do without building cities... Among other things, volcanic ash itself is an excellent fertilizer for plants, containing many compounds of the elements of potassium, nitrogen, etc., and over time turning into fertile soils. Therefore, gardens are planted near volcanoes and fields are cultivated.

In addition to practical benefits, the study of extinct, ancient and already destroyed volcanoes allows volcanologists to accumulate a lot of interesting and useful information not only for the study of volcanoes, but also for geology in general. The study of ancient volcanoes, active tens of millions of years ago and almost level with the surface of the Earth, helps to understand a lot. For example, studying volcanic activity on the territory of the Kuril ridge helps us understand the formation of the Kuril ridge itself, and many other ridges, such as the Ural ridge and a number of others.

This happened among the ancient Devonian sea, which for about 300 million years covered the area where the Eurasian continent emerged from Pangea with the Ural ridge separating Europe from Asia. Modern geology is able to trace ancient processes in the Earth's crust through traces left by natural disasters. Geologists identify layers of cracks and faults at the bend earth's crust, which was previously an underwater platform. Magma repeatedly rose from the depths of the sea along cracks and faults. Its underwater eruptions, as lava accumulated from the bottom of the sea to the surface of the water, were replaced by surface volcanoes, which formed the islands, i.e. The result was the same picture that is now observed on the border of the Sea of ​​Okhotsk with the Pacific Ocean. The volcanoes of the Urals, along with lava outpourings, also ejected a mass of fragmentary volcanic material, which settled in the eruption area, expanding the area of ​​the volcanic island and closing the gaps between the islands. Thus, volcanic islands gradually connected with each other. This unification was helped, of course, by the movements of the earth’s crust and some other processes, as a result of the combined influence of which the Ural mountain range arose, so rich in gems and copper ores.

Active volcanoes

Most modern active volcanoes are located in the Himalayan-Alpine belt and the Pacific "Ring of Fire". Terrestrial and currently active volcanoes include, according to various estimates, from 300 to 500 volcanoes. Of these, from 5 to 15 are active every month, releasing hot gases and lava. Active volcanoes sometimes “sleep” for several years or even decades. But hot gases and lava continue to bubble in their depths. Sometimes, due to the active seething of lava in the depths of the volcano, a volcanic tremer (volcanic tremor) occurs, causing several series of small earthquakes.

When, under the influence of processes occurring in the mantle and core, magma moves upward, it presses on the Earth’s crust, like steam from boiling water on the lid of a kettle, and the lid seems to “dance” and tremble if there is an excess of water in the kettle. Like steam from under the lid of a kettle, hot lava gases escape from under the rocks that litter the crater floor, from crevices and cracks on the floor and slopes of the crater. Vapors of hot underground waters and hot gases burst out violently, with hissing and whistling. earth's bowels, filling the crater bowl with suffocating gases. Cooling on the surface and rising upward, the gases form a cloud above the top of the cone, about which they usually say: the volcano is “smoking.” For months and years, the volcano can “calmly” smoke until there will be an eruption.

An eruption of an active volcano can last for several days, sometimes months or years, after which the volcano calms down again and seems to “fall asleep” for many months or years until the bottom of the crater explodes under the pressure of gases escaping from the bowels of the Earth. Then, with a deafening explosion of sound, thick black clouds of gas and water vapor are thrown up from the crater thousands of meters and even tens of kilometers (depending on the intensity of the eruption). This huge black cloud is always illuminated with blood-red reflections. They arise from red-hot huge stones, giant pieces of red-hot rock, thunderously thrown by an explosion to the surface and accompanied by giant sheaves of sparks against the backdrop of a black gas cloud.

Here, by the way, it is appropriate to say that not all active volcanoes erupt in this way. They erupt in different ways. From some, fiery rivers of liquid basaltic lava simply and “quietly” flow out, burning everything in its path, and with weaker eruptions, only periodic cannon shots occur in the crater of the volcano; these are gas explosions. Sometimes, during gas explosions, pieces of hot, glowing lava, hot rock and fragments of pumice fly out of the crater. In the case of lower temperatures, already completely solidified lava is thrown out of the crater and crushed, and large blocks of dark, non-luminous petrified volcanic ash (tephra) rise up. But there are volcanoes that erupt with all their might, throwing black and red clouds of gases into the atmosphere, spewing hot blocks of rock, tephra, hot volcanic ash and fiery rivers of lava onto the ground. These volcanoes are the most dangerous.

Strictly speaking, the manifestations of volcanic earthquakes are, in principle, almost no different from the phenomena that occur during tectonic earthquakes. Both are accompanied by a number of natural phenomena: explosions of huge amounts of water vapor and gases, as well as seismic and acoustic vibrations. The fact is that the movement of magma, both during tectonic earthquakes and in the depths of a volcano, is accompanied by cracking of rocks, and this, in turn, causes seismic and acoustic radiation. Therefore, the areas, causes and the very mechanism of modern volcanism coincide with the zones, causes and mechanism of tectonic earthquakes. The causes of volcanic eruptions and accompanying earthquakes are the action of tectonic forces on rocks. The very mechanism of formation of seismic waves during volcanic earthquakes is the same as during tectonic ones. The processes taking place in the mantle have a direct impact on the earth's crust and surface. They are the direct cause of all earthquakes, all volcanic eruptions, as well as the movement of continents, the formation of mountains and the formation of ore deposits.

Under the influence of processes occurring in the mantle and core, magma, this molten rock saturated with gases, moves upward, and, as the magma moves upward, the number of volatile components in it decreases. Foci of magma are located under the earth's crust, in the upper part of the mantle, at a depth of 50 to 100 km. Under strong pressure from the released gases, magma, melting the surrounding rocks, makes its way and forms a vent, or channel, of the volcano. The gases, cooled and thus released, clear a path through the vent in explosions, break apart solid rocks and throw pieces of the vent along with the hot rock to a great height. This phenomenon always precedes the outpouring of lava. Just as carbon dioxide tends to escape when a bottle of champagne or carbonated drink is uncorked, forming foam, so in the crater of a volcano, foaming magma is rapidly ejected by the gases released from it. Having lost a significant amount of gas, magma pours out of the crater and flows along the slopes of the volcano. Degassed magma erupted to the surface during the next volcanic eruption is called lava. Lava can vary in composition - liquid, thick or viscous. Liquid lava spreads relatively quickly along the slopes of the crater, forming lava falls along its path. Thick lava flows slowly, constantly breaking into blocks that pile on top of each other, releasing gases. Viscous lava comes out even more slowly and thickly, constantly sticking together into blocks, which are scattered and thrown high by the explosions of gases coming out of it.

Distribution of volcanoes

During the formation of our planet, volcanoes covered, according to all geologists, its entire surface. Over time, when the volcanoes that formed the modern face of the Earth ceased their activity, new volcanoes continued to arise only along large faults in the earth's crust. Most of the ancient volcanoes have not survived, as mountain-building processes and river erosion destroyed them. But volcanic mountains, which are now found on the surface of our planet, arose relatively recently - in the Quaternary period. Modern volcanoes concentrated on Earth along certain zones (belts) characterized by high tectonic mobility. These belts usually occur destructive earthquakes; The heat flow from the bowels of the Earth here is several times higher than in quiet areas.

Volcanoes are distributed unevenly across the face of the Earth. In the northern hemisphere there is a significant number of more volcanoes than in the south. But they are especially common in the equatorial zone.

In such areas of both continents as the European part of the USSR, Siberia (without Kamchatka), Brazil, Australia and others, there are almost completely devoid of volcanoes. Other areas - Kamchatka, Iceland, the North-West coast and the islands of the Mediterranean Sea, the Indian and Pacific Oceans and the west coast of America - are very rich in volcanoes. Most volcanoes are concentrated on coasts and islands Pacific Ocean(322 volcanoes, or 61.7%), where they form the so-called Pacific "Ring of Fire". According to some sources, there are 526 volcanoes in this ring of fire. Of these, 328 erupted in historical times. Although Russia is not a southern country, there are about a thousand volcanoes in Kamchatka. Volcanologists explain their abundance by the fact that Kamchatka is located in the area of ​​the Pacific “ring of fire”, which at its edge touches Japan and Kamchatka with the Kuril Islands. On our territory, the Pacific Ring of Fire includes volcanoes Kuril Islands(40) and the Kamchatka Peninsula (28). The most active volcanoes in terms of frequency and strength of eruptions are Klyuchevskoy, Narymsky, Shiveluch, Bezymyanny, and Ksudach.

The Pacific volcanic ring of the Earth stretches from Kamchatka to the south, capturing the islands of the Kuril, Japanese, Philippine, New Guinea, Solomon, New Hebrides and New Zealand, almost reaching Antactis. But it is near Antarctica that the “ring of fire” of the Pacific Ocean is interrupted, and then continues along the west coast of America from Tierra del Fuego and Patagonia through the Andes and Cordillera to the southern coast of Alaska and the Aleutian Islands. The Pacific Ring of Fire also includes the central Pacific Ocean with the volcanic group of the Sandwich Islands, Samoa, Tonga, the Kermadecs and the Galapagos Islands. Thus, the Pacific Ring of Fire contains almost 4/5 of all the Earth’s volcanoes, which have manifested themselves in more than 2000 eruptions in historical times.

The second large volcanic belt stretches across the Mediterranean, the Iranian plateau to the Sunda archipelago. Within its borders there are such volcanoes as Vesuvius (Italy), Etna (the Sicily peninsula), Santorini (Aegean Sea). The volcanoes of the Caucasus and Transcaucasia also fall into this belt. On the Greater Caucasus Range there are two volcanoes, Elbrus (5642 m) and the double-peaked Kazbek (5033 m). In Transcaucasia, on the border with Turkey, there is the Ararat volcano with a cone covered with a snow cap. A little to the east, in the Elborz ridge, framing the Caspian Sea from the south, is the beautiful Damavand volcano. There are many volcanoes (63, of which 37 are active) in the Sunda archipelago (Indonesia).

The third major volcanic belt stretches along Atlantic Ocean. There are 69 volcanoes, of which 39 erupted in historical times. Largest number volcanoes (40) on the island of Iceland, located along the axis of an underwater mid-ocean ridge, and 27 of them have already declared their activity in historical time. Iceland's volcanoes erupt quite frequently.

The fourth volcanic belt is relatively small in size. He takes East Africa(Beyond these four volcanic belts, volcanoes are almost never found on continents. In vast areas of Central and Northern Europe, in most parts of Asia, in Australia, in North and South America, excluding the Pacific Rim, they are absent. But in the oceans the picture is completely different A detailed study of the topography of the ocean floor conducted over the past two decades has shown that there are a huge number of large oceans at the bottom of all oceans without exception. volcanic buildings. Especially many of them were found on the bottom of the Pacific Ocean (Fig. 7). Most interesting feature What makes most underwater volcanoes so special is that their tops are flat. Scientists have found that such flat tops of volcanoes were formed when these volcanoes protruded from the water. The waves eroded the cone sticking out of the water, forming an almost flat surface. Subsequently, the ocean floor sank and these topless volcanoes, called guillotines, became submerged.

Atlantic-Himalayan volcanic belt

The Mediterranean volcanic area of ​​the Earth belongs to the Atlantic-Himalayan belt, which stretches from the extreme west of the European continent to the southeastern tip of Asia, including the islands of the Malay Archipelago. This volcanic belt of Europe is divided into several belts, covering several zones.

Also included in the Indian zone are the volcanoes of the Arabian Peninsula with signs of young volcanic activity. Signs of young volcanism in Arabia and Asia Minor are the vast basalt plateaus of the northern part of the Arabian Peninsula, fresh volcanic cones in the vicinity of Damascus, and finally, two volcanic eruptions in historical times in Western Arabia and an underwater eruption near Aden.

The Indian zone of volcanic activity includes two known in Antarctica active volcano: Erebus and Terror, although among scientific volcanologists many believe that the Antarctic volcanoes belong to the Pacific Ring of Fire. In our opinion, since the Pacific and Atlantic volcanic filaments converge in the area of ​​Antarctica, the volcanoes of Antarctica can be attributed to any “ring”, both the Atlantic and the Pacific.

Thus, if we draw up one map of the location of volcanoes, both dormant and active, we will understand that the entire earth is tightly gripped by a volcanic vice, consisting of two giant components - the Pacific “ring of fire” and the Atlantic-Himalayan “belt of fire”.

BAKU, April 19 - "News-Azerbaijan". A huge amount of ash released into the atmosphere after the eruption of the Eyjafjallajokull volcano in Iceland paralyzed air traffic in most of Europe, RIA Novosti reports.

Below is background information about dormant volcanoes on Earth.

A volcano that has never erupted in 10,000 years is called dormant. The volcano can remain in this state for up to 25,000 years. If it has never erupted before, it is considered extinct.

Mount Fuji (Fujiyama) is a dormant volcano (according to other sources, active), whose last eruption occurred in 1707. It is located 150 kilometers southwest of Tokyo and, together with the adjacent area, is included in national park Fuji-Hakone-Izu.

The most high mountain Japan has an ideal conical outline and is an object of special honor for the Japanese.

Elbrus is a dormant volcano lying north of the Main Caucasus Range, has two main peaks 5621 m (eastern) and 5642 m (western). The western peak of Elbrus is the highest point in Europe. Are the peaks separated by a saddle? 5200 m and are separated from each other by approximately 3 km.

According to scientists, in last time Elbrus erupted approximately 1,700 years ago (according to some sources in the 12th century AD). This eruption was accompanied by powerful mudflows and fires, and traces of ash were found at a distance of 300 kilometers from the crater.

Scientists tried to simulate possible situations in the event of an Elbrus eruption, and the data turned out to be disappointing, especially considering that when last eruption he “launched” powerful volcanic “bombs” over 700 kilometers and they ended up in the vicinity of modern Astrakhan. One has only to look at the map, estimate the distance, and it becomes clear what kind of power lies in this giant. If an eruption occurs, magma heated to several thousand degrees will begin to melt thousand-year-old glaciers, and mudflows will destroy the picturesque areas of the Elbrus region. A sharp rise in the level of Caucasian rivers, such as Baksan, Malka, Kuban, Terek, Podkumok, Kuma, will cause unprecedented floods. Tons of erupting ash will cover vast areas. According to some reports, hot magma can even reach the Black Sea coast of the Caucasus.

Dormant supervolcanoes on Earth are the Long Valley volcanoes in California, Toba on the island of Sumatra, Taupo in New Zealand, Yellowstone and Kamchatka supervolcanoes.

The open caldera of the Kamchatka supervolcano is a giant oval about 35 kilometers long. The caldera begins in the upper reaches of the Paratunka River and ends behind the Bannye thermal springs. Scientists believe that these sources, in particular, are fueled by the heat of an ancient supervolcano. The last time the supervolcano erupted was one and a half million years ago. It was believed that there were no such ancient volcanic formations in Kamchatka, since it is seismologically much younger.

The last eruption of the Tobo supervolcano occurred 74 thousand years ago in the area of ​​​​what is now the island of Sumatra in Indonesia. After the explosion, a column of hot gas and ash burst out of the ground at supersonic speed, which almost instantly reached the edge of the stratosphere? 50 km mark. In three days, more than 2,800 cubic kilometers of magma poured onto the surface: in some places the thickness of solidified lava? tens of meters. When the volcano's dome collapsed inward, giant, hot clouds of ash rose into the air. They moved at a speed of almost 400 km per hour, melting stones in their path and burning out all living things. After the eruption, colorless ash fell over an area with a radius of 300 km for several weeks. The sun was not visible for six months. Temperatures across the entire Earth dropped by 15 degrees.

According to the leading expert on supervolcanoes, Professor Bill McGuire of the Banfield Graig Hazard Research Center in London, the Yellowstone and Toba supervolcanoes are two places to watch first.

On the ruins of a volcano in Yellowstone, the Americans built the world-famous Yellowstone national park. Here are the largest geyser fields in the world: 3 thousand geysers and 10 thousand hot thermal and mud springs fed by the heat of the large volcano on the American continent, which last raged 642 thousand years ago.

Until 2004, it was believed that the underground giant was immersed in a “lethargic” sleep, which would end in final attenuation, but the volcano began to stir: the earth’s crust began to rise in some places. According to data from the global navigation satellite system GPS, as well as radar measurements from satellites, the soil is rising at a rate of 7 cm per year, more than triple the average since the 1920s. Other signs of geological activity were also noted: new powerful geysers with hot streams appeared, and the old ones dried up.

According to seismologists at the Yellowstone Volcanic Laboratory, most likely the main driving force the process of raising the earth's crust - the natural circulation of cold and hot layers of lava. However, scientists do not rule out the accumulation of magma that could cause a new eruption. Currently, magma here lies at a depth of more than 10 km. The area of ​​molten rock is estimated to be comparable in size to Los Angeles.

According to Bill McGuire, the possibility of a supervolcano eruption is 12 times greater than that of a meteorite.