How magma differs from lava
The mantle of the Earth is 30 kilometers under your feet. This is an area of super-hot rock that extends to the core of the Earth. It is so hot that the molten rock forms giant bubbles of liquid rock called magma chambers. This magma is lighter than the surrounding rock, therefore it rises upward, looking for cracks and weaknesses in the earth's crust. When it finally reaches the surface, it erupts from the ground as lava, ash, volcanic gases and rocks. It is called magma underground, and lava when it erupts.
Volcanoes can be active, dormant or extinct
An active volcano is one that has erupted in historical times (in the last several thousand years). A dormant volcano is one that erupted in historical times and can erupt again. An extinct volcano is one that, according to scientists, will not erupt.
Lava fountain in Hawaii
Volcanoes can grow rapidly
While some volcanoes form over thousands of years, others can grow overnight. For example, the cinder cone of the Paricutin volcano appeared in a Mexican cornfield on February 20, 1943. A week later, it was 5 stories high, and by the end of the year it had grown to 336 meters. Its growth ended in 1952 and stopped at around 424 meters. By the standards of geologists, this is pretty fast.
About 20 volcanoes are erupting right now
Somewhere in the world, about 20 active volcanoes are erupting as you read this. Some are just starting, others are continuing. 50-70 volcanoes erupted in the past year and 160 have been active over the past decade. Geologists estimate that there have been about 1,300 eruptions in the past 10,000 years. Three quarters of all eruptions occurred at the bottom of the ocean, and most of them continue to operate, but geologists are not aware of this. If you add submarine volcanoes, in total, about 6,000 volcanoes have erupted in the last 10,000 years.
Volcanoes are dangerous
But you, of course, have heard about this. Some of the deadliest volcanoes include Krakatoa, which erupted in 1883 in a tsunami that killed 36,000 people. In 79 A.D. e. Vesuvius exploded, burying the cities of Pompeii and Herculaneum, killing 16,000 people. The Mount Peli volcano on the island of Martinique destroyed the city of 30,000 in 1902. The most dangerous moment in a volcanic eruption is pyroclastic flows that move along the side of the volcano at a speed of hundreds of kilometers per hour with a temperature of over 1000 degrees Celsius. 
Eyjafjallajökull volcano eruption
Supervolcanoes are really dangerous
Geologists measure volcanic eruptions using the Volcanic Explosion Index, which measures the amount of material released. A "small" eruption like St. Helens was 5 out of 8 points, spewing out a cubic kilometer of material. The largest eruption is considered Toba, which happened 73,000 years ago. It released over 1,000 cubic kilometers of material and created a caldera 100 km long and 30 km wide. The explosion plunged the world into an ice age. According to the index, the eruption of Toba was rated at eight.
The highest volcano in the solar system is not on Earth
The highest volcano in the solar system is not on Earth, but on Mars. Mount Olympus is a giant shield volcano that rises 27 kilometers in height and is 550 kilometers across. Scientists believe that Mount Olympus was able to grow so large because Mars does not have any plate tectonics at all. Even one hotspot could swell over billions of years, pulling the volcano higher and higher.
The tallest and largest volcanoes on Earth are nearby
The tallest volcano on Earth is Mauna Kea in Hawaii; its height is 4207 meters. It is slightly taller than the largest volcano on Earth, Mauna Loa, with a height of 4169 meters. Both are shield volcanoes that rise from the ocean floor. If you could measure Mauna Kea from its bottom in the ocean to its very peak, you would get 10,203 meters (higher than Everest itself).
The farthest point from the center of the Earth is a volcano
You may be thinking that the summit of Mount Everest is the farthest point from the center of the Earth, but this is not the case. This is actually the Chimborazo volcano in Ecuador. The fact is that the Earth revolves in space and is a geoid. Points at the equator are farther from the center of the earth than at the poles. And Chimborazo is very close to the equator of the Earth. Although its height is "only" 6267 meters.
Walking on the body of a sleeping volcano, capable of destroying huge territories in an explosion - Crimea, the entire Black Sea, half of Ukraine and part of Russia ...
Therefore, to find out that he is the oldest sleeping man in the world, and 150 million years ago, he changed everything in these places to a significant extent ...
But many of you have been here once. And they went.
Karadag, south-east of Crimea. One of the most beautiful and legendary places on the peninsula.
And a giant sleeping natural bomb. She will get tired of the person, she will not regret anyone
2. A sight familiar to many vacationers in Crimea - the Karadag massif on the horizon, which stands out far into the sea. Looking at it from this point, you cannot immediately say that a volcano once erupted here, completely changing the landscape of the vast adjacent territories ...
Kiev volcanologist Stepan Romchishin says that the Karadag volcano did not die 150 million years ago, but can potentially wake up even now, - "If Karadag explodes, Crimea will not be there until the end of the day. A cloud of volcanic ash will destroy all life to Dnepropetrovsk. The ash column will rise. 50 kilometers, and the magma will flow out for several days. During the eruption, a cavity forms under the volcano, so it falls into the abyss, and then explodes. The force of such a volcano can be equated to a hundred atomic bombs. "
The scientist assumes that from the explosion the ash heated to 200 ° C will scatter over a huge area - up to the Russian city of Smolensk in the north and part of the territory of Turkey and other Black Sea countries in the south, west and east. The sea wave speed will reach 400 km / h.
For example, the last most powerful volcanic eruption, according to scientists, was 74 thousand years ago in New Zealand. It almost became fatal to humanity. Millions of tons of ash and sulfur were thrown into the air. Temperatures around the world have dropped by 15 degrees. The ash hovered in the atmosphere and did not let the sun's rays through. Sulfur rains have destroyed almost all forests in Asia. Then it took more than 300 years to restore nature. 
3. Karadag is very different from all other mountain ranges in the Crimea. A chaotic conglomeration of ominous black rocks directed in different directions, inaccessible gorges and gaps, stone walls falling off into the sea and forming inaccessible bays from the coast, stern stone figures of the Meter City.
All this is a consequence of a volcano that operated here 150 million years ago. 
4. Diverse and unusual landforms of the volcanic massif with a very complex geological structure appeared already in later periods during weathering and erosion. The gentle and flat continental slope of the Coastal Range is protected, like armor, from destruction by a powerful vast lava flow ... 
5. And the opposite slope, facing the sea, is completely different. It is heavily dissected and difficult to pass, cut by gorges and surrounded by inclined ridges of lava flows stretching along the slope. 
6. The modern bowl of the Karadag (and if you look at the heights of the Karadag, today it is exactly the bowl, the walls of which consist of ridges and peaks) is very diverse both in relief and in landscape. Standing at one point, looking in one direction, you will see quite familiar mountain peaks overgrown with grasses and bushes, forming a rather familiar Crimean landscape, and looking in the other direction ... 
6. ... you will see the rocks of the Dead City, on which for many thousands of years at least some vegetation has barely been able to catch on. And that is not everywhere. 
7. He is therefore dead, because many rocks rise as black dead idols, as if in the famous fantasy Mordor 
8. Diverse in appearance and mineral composition, the volcanic rocks of Karadag were formed during the solidification of lava. Pillow lava flows are very common. This is a chaotic heap of cushion-shaped, ellipsoidal and balloon-shaped lava segregations with smooth contours, and each of them has a continuous cooling surface with a hardened crust. Pillow flows are especially effective on the southern slope of the Magnetic Ridge, along which they stretch obliquely in the form of powerful inclined stone walls. There are seven streams with a thickness of 15 - 25 m each. 
9. The most diverse lava compositions are on the slopes of the Karagach ridge. There are five types of rocks, interconnected by gradual transitions. The change of rocks from bottom to top occurs in the following order: keratophyr - partially albitized porphyrite - porphyrite - bipyroxene andesite - glassy andesite. It is of them that the very famous Rocks-Kings consist 
10. But starting from the name and types of rocks, so as not to make a hole in my own and your brain, I can only say that there are some incredible numbers of them here.
Each breed in its own way forms rocks and stones into a variety of shapes. 
12. Separately, it should be said about various craters and places where lava emerges to the surface. There are several remains of craters on Karadag. The most famous of them is the Devil's Fireplace. 
13. Perfectly preserved, spectacular, beautiful classical concentric form - a perfect example of a subvolcanic body. 
14. The second striking representative of the crater is the Ivan-Robber rock, which I am talking about separately. Remember the cork that plugged the mouth of the volcano? 
15. Vent itself close-up 
17. Here is another part of the giant circle - the Sail rock 
21. Numerous dikes should be mentioned separately. A dike is a frozen plate-like intrusion of magma, prepared by weathering from the surrounding less persistent rocks. The most famous Karadag dike is the Lion's Dike. Located under the Devil's Kamin crater, it is surrounded by several more small and one large dikes. In addition, the structure of the Coastal Range in relation to the Khoba-Tepe ridge allows scientists to assume that it was here that the main mouth of the volcano was located. 
22. Sometimes there is a whole "stone forest" of giant teeth, peaks and stone teeth, which are formed in thick layers of volcanic tuffs, dissected by vertical cracks. These are all the dykes surrounding the Lion Dyke 
23. Starting at a height of several hundred meters, giant ridges descend to the sea 
24. Some of them literally cut through mountain ranges. And weathering over many thousands of years on both sides of the ridge has formed gorges. 
25. Under some ridges "descending" from the mountains, caves have formed, including underwater ones. One of them is the Thundering Grotto. It was the sounds from this grotto that formed the famous legend about the Karadag snake, which, it seems, someone once saw, and many often heard its roar in the fog. This legend even formed the basis for the story "Fatal Eggs" by Mikhail Bulgakov. 
26. The famous Golden Gate - an outlier rock, towering over a hole in the sea and also generated by a volcano 
27. Figures-remnants at the entrance to the Dead City 
28. Outlets of various breeds are found almost at every step 
29. As if frozen foam 
30. In addition to the geological composition and the variety of different forms, the rocks are striking with their color schemes. 
31. Columnar units are found everywhere. I can imagine how much lava was poured here 150 million years ago. 
32. Lava flows 
33. Autumn Levinson-Lessing rock unusual structure. 
34. But with regard to the possibility of an explosion of the Karadag volcano in our time, according to scientists, its probability is only 0.00000 and what is there percent. It will sleep for a long time, because it is not located at the junctions of tectonic plates, but precisely from their collision, the earth splits ... So you can sleep peacefully) 
My previous photo reports and photo plots:
The average person does not see much difference between "extinct" and "dormant" volcanoes. In fact, the differences are very significant, because a conditionally "dormant" volcanic formation can suddenly awaken, and then no one will seem little.
Another thing is that they are completely safe, which is actively used by travel companies and outdoor enthusiasts. What are the main features of extinct volcanoes?
Physics of a volcanic eruption - how it becomes extinct
The eruption occurs due to the presence in magma not only of water vapor, but also of various gases: hydrogen chloride and fluoride, sulfur oxides and, methane, nitrogen, carbon dioxide, etc.
In a "dormant" volcano, the concentration of gases dissolved in magma corresponds to the pressure level under which the magma is located at a certain depth. In this way, a state of equilibrium is maintained.
However, due to earthquakes that shift parts of the crust, a decrease in pressure may occur, for example, in the region of a magma chamber. The state of equilibrium is violated and the gases immediately increase in volume due to the transition to a gaseous state.
The foamed magma begins to move upward, which leads to an even greater drop in pressure, and therefore to the acceleration of the process of gas release from the magma.
Accordingly, the probability of his awakening tends to zero.
List of famous extinct volcanoes in the world
Volcanoes, which do not pose any threat, are located on all seven continents: in the Americas, Asia, Africa, Europe, Antarctica and Australia.
Today there are over two hundred extinct volcanoes in the world. The most typical representatives of this type are presented below.
Rocky
This extinct volcano is located on the Kamchatka Peninsula, in the very center of the Sredinny Range. The highest point of the volcano is 1759 meters above sea level.
According to geologists, Stony was last active about two and a half million years ago. The volcano was formed by lava flows and pyroclastic rocks. The volcanic shape in the form of a gentle cone ends not in a crater destroyed due to erosion, but a steep summit.
Arayat
Located in Luzon, the largest island in the Philippines. The highest point is 1025 meters.
The last eruption most likely occurred about 10 thousand years ago. Despite the erosion that hit the northern and western parts of the crater, it still survived at the summit.
Damavand
It is located in the Iranian province of Mazandiran and is the highest point of the Elburz mountain range (5620 meters above sea level). The last eruption was recorded around 5350 BC.
Demavend has the shape of a gentle cone and rises one and a half kilometers above Elburs. The volcanic cone was created by andesitic lava, but glaciers are also present on the slopes.
Sajama
Located in Bolivia, in the Central Andes. The highest point above sea level is 6542 meters. Sahama is part of the National Park of the same name, located near the Chilean border.
The exact date of the last activity is not known for certain, but many scientists insist on the era of the Quaternary Holocene, i.e. about 12 thousand years ago.
Sahama is a classic cone-shaped stratovolcano composed of solidified lava and its fragments. At an altitude of over 6,000 meters, it is covered with never-melting snow and ice.
Aconcagua
It is considered the highest extinct volcano located in the same Andes, but on Argentine territory. The summit is located at 6961 meters above sea level.
Aconcagua, he is considered not only the record holder among his fellows, but also the highest point of the southern and western hemispheres. For these merits, he even got into the list of the highest peaks of the six parts of the world "Seven Summits".
Aconcagua is also one of the oldest volcanic formations on the planet.
The exact date is unknown, but many scientists conclude that it originated about 150 million years ago.
Excursions to extinct volcanoes
A traditional excursion lasts 1-2 days and involves either ascent to the peaks by helicopter, or on foot.
Some volcanoes are even equipped with special areas where tourists can take a break and enjoy the natural views from high altitudes.
Extinct volcanoes are not only a living reminder of the great power of nature.
Thanks to their large number anywhere in the world, anyone can organize an appropriate tour and get an unforgettable experience.
Scientists around the world have noted a sharp increase in volcanic activity on the ground. Many "sleeping" volcanoes began to show signs of life. Of particular danger are the so-called supervolcanoes, the force of the eruption of which is equal to the explosion of several nuclear bombs at the same time. The possibility of their eruption is 12 times greater than the fall of a meteorite. The probability that this will happen in our lifetime is 0.15%, experts say. "Ytro" compiled a rating of hidden volcanoes that can wake up at any moment.Ubehebe
In the list of awakening volcanoes, this one is not yet the scariest one. Located in an intermontane depression called Death Valley in the California Mojave Desert, the crater is 1 km wide and 237 m deep. The magma that accumulates in its bowels can meet with groundwater, which will cause a fairly strong explosion. The gases will escape to the surface at a speed of 320 km / h, but since the volcano is located in a deserted desert, a person will not suffer from its eruption.
Katla
Much more serious will be the consequences of the eruption of the Katla volcano, which on December 2, 2011 showed signs of life. This giant, hidden in the thickness of one of the largest glaciers in Iceland, threatens Europe with serious cataclysms. The diameter of its crater is 10 km, so the eruption can cause a catastrophic flood, melting the glacier, causing hundreds of thousands of cubic meters of water to rush into the Atlantic, sweeping away everything in its path. The ash cloud will become so dense that the sun's rays will be reflected, due to which the planet will overtake a cold snap. There is no need to talk about the poisonous properties of pungent smoke - all living things will die out within a radius of several kilometers.
Uturunku
And a month earlier, in October 2011, scientists noted the activity of the Bolivian Uturunku, which inexorably quickly accumulates magma, which means it will also explode soon. And the forecasts are not encouraging at the moment. Ashes and sulfur gases, when released, can reach the stratosphere and, like a blanket, cover the globe. The gases are converted into sulfuric acid, which will fall on the Earth along with precipitation. A similar effect will be caused by an anticipated nuclear winter.
Yellowstone caldera
One of the most dangerous volcanoes on Earth is considered a supervolcano lying in the Yellowstone National Park in the US state of Wyoming. In fact, the entire park is located in the caldera, that is, in the hollow of the volcano. Its eruption will give rise to a cataclysm of a planetary scale. All living things will perish for thousands of kilometers around, lava flows can cover half of the United States, and ash will envelop the Earth. The global temperature will drop by several degrees at once.
Toba
The volcano from the island of Sumatra is known for the most powerful eruption in the history of mankind. About 70 - 80 thousand years ago, he threw out so much lava that it could cover the entire territory of Russia with an eight-centimeter layer. The ash column rose 50 km and reached the edge of the stratosphere. Due to the onset of a volcanic winter, the number of living beings, including humans, has sharply decreased. Because of this, evolution literally stopped for a while.
Taupo
Beneath a picturesque lake on New Zealand's northern island lies a dormant volcano. After a powerful explosion 26.5 thousand years ago, when about 530 cubic kilometers of magma poured onto the surface, covering 80 km around, the water filled the formed caldera. Now the volcano is calm, but the eruptions of such giants usually occur at intervals of a thousand years.
Long Veli
The crater of the volcano, which is located in the state of California, next to Mount Mammoth, reaches 2600 meters. It last erupted 700 thousand years ago. Then the hot magma burned out everything for thousands of square kilometers around. Volcanic ash covered almost the entire western United States.
Teide
The third largest volcano in the world is located in Tenerife, one of the Canary Islands. Teide is currently inactive, but the risk of an eruption is very high. The International Association of Volcanologists named it one of the most dangerous volcanoes in the world. In an explosion, a colossal boulder can break off from it, which, when falling into the ocean, will cause a powerful tsunami.
Vesuvius
The Neapolitan volcano has already shown its destructive abilities once. In the 1st century. BC. a powerful eruption destroyed the Roman cities of Pompeii and Herculaneum. Then 25 thousand people died. Now Vesuvius is silent, but this also raises concerns. Experts believe that the longer the resting period lasts, the stronger the imminent eruption will be. The ashes that break free can cover the entire territory of southern Europe.
Elbrus
It is expected that this giant could wake up in 50 years. During the eruption of Elbrus, the melted snow will lead to the descent of a volcanogenic mudflow from the eastern slope, which will spread for 50 kilometers. The flow rate will be up to 20 m / s. This can cause a real disaster, since the city of Tyrnyauz is located nearby, where more than 20 thousand people live.
The most popular way to classify volcanoes is ...
The frequency of their eruption. Those that erupt regularly are called active. And those that exploded a long time ago, but have now calmed down, are called sleepers. In the end, it all comes down to timing.
Active
There is currently no consensus among volcanologists about what is the main criterion for activity. Volcanoes, like all geological things, have a long lifespan (up to millions of years). And over the past several thousand years, many volcanoes have erupted many times, but currently do not show signs of magmatic life.
Thus, the term "active" can mean activity only from the point of view of the safety of human lives. Therefore, geologists often consider a volcano to be active only if it is hooligan in some way. That is, it creates earthquakes or gas emissions, which means that it is about to explode.
The Smithsonian Global Volcanism Program defines a volcano as active only if it has erupted in the past 10,000 years.
Another criterion for the activity of a volcano is considered to be its eruption in the course of human history. This is what the International Association of Volcanology does.
Thus, the definition of "active volcano" best fits those that are currently in a state of regular eruption.
Sleeping
These are capable of erupting in the future, but will have to wait a very long time. Or not.
It is difficult to define such volcanoes because it is difficult to distinguish between a volcano that is simply inactive and one that will remain inactive forever.
Such volcanoes are often considered extinct if there are no written records of its activity. However, they may simply remain dormant for a long period of time. For example, the volcanoes Yellowstone, Toba and Vesuvius were considered extinct before their new destructive eruptions.
Therefore, a dormant volcano is, in fact, active. It's just that it's not erupting right now.
Extinct
These volcanoes were cut off from magma reserves. There are many extinct volcanoes around the world, many of which are found in the Hawaiian-Imperial Pacific Ridge. And sometimes they stand separately.
For example, the Shiprok volcano, which rises in the territory of the Navajo people in New Mexico. This is a classic single extinct volcano. And Edinburgh Castle, located near the capital of Edinburgh in Scotland, is located on top of an extinct volcano.
But determining whether a volcano is really extinct is often difficult. After all, some volcanoes have existed for millions of years. Thus, some volcanologists call extinct volcanoes inactive. And vice versa.
PS
When it comes to geological features, time mercilessly repels our attempts to understand and measure the magnitude of earthly events. After all, we are mere mortals. People and generations have a limited life cycle and even an entire civilization can become dust, while one volcano slowly rubs its eyes after a long sleep to explode.
But it's time for you to wake up before we go on vacation. Otherwise, you will be left without suitable ones.
