(ORDO NEWS) — A volcanic eruption is more than just a natural disaster. Just imagine that fragments of rock are falling on you from the sky, there is a column of ash in the air, and essentially molten earth is pouring on you from the slope of the “mountain”. Horror, huh? It doesn’t even look like a disaster movie, but like a real apocalypse. However, even in recent human history, there have been very serious volcanic eruptions.
They not only claimed lives, but also buried entire cities. All due to the fact that a person simply cannot oppose anything to such an element. Even earthquakes and tsunamis are not as bad as this. If just an eruption is scary, then imagine what the most powerful of them were.
What causes a volcanic eruption
You can talk a lot about volcanic eruptions and give examples of what causes them. There are different types depending on the intensity, the accompanying phenomena and where it all takes place. In the end, do not forget that there is even a division into ordinary volcanoes and underwater ones.
First of all, one must understand that the earth’s shell is called the lithosphere and it is on it that we all live. The thickness of this layer is about one percent of the Earth’s diameter, and in absolute terms it is about 70-80 kilometers on land and 20-30 kilometers on the ocean floor. The lithosphere consists of plates, between which there are faults. It is these faults that are the places of the most probable volcanic eruptions.
There is a mantle under the lithospheric plates, which is heated to several thousand degrees. In consistency, it is similar to a thick resin, and it is on it that lithospheric plates “float”. When the plates move, they find themselves on top of each other and the part that turns out to be below begins to melt and the product of such a fused is called magma.
Magma is lighter and more liquid than the mantle, and because of this, it accumulates directly under the lithospheric plates. As a result of such an accumulation and pressure increase due to the boiling of the rock and water vapor, it begins to look for an exit to the surface. As a result, where the weak point is, there will be an eruption. Sometimes magma finds an easy outlet and flows gradually without causing an explosion. If this is not possible, then trouble is inevitable. Especially when it comes to dormant volcanoes that have not erupted for a long time, but the pressure has been accumulating under them. The more it accumulates, the more powerful the eruption will be.
Classic volcanoes are called stratovolcanoes. They are conical in shape and consist of various eruption products. They are usually found where one tectonic plate goes under another. Magma in this case is located as close to the surface as possible, and therefore stratovolcano eruptions are often very powerful.
The most powerful volcanic eruptions
Now that everything is clear with the “technology of eruptions”, we can talk about which eruptions were the most powerful in the history of mankind in recent times. We all remember Vesuvius, who buried Pompeii, and Eyjafjallajökull, which erupted several years ago and temporarily paralyzed air traffic in Europe. In addition to these eruptions, there were others, much more interesting and / or large-scale.
Vesuvius eruption – 79
It is without Vesuvius, whose name is closely associated in the memory of many with the name of the city of Pompeii, that the story of the volcanoes would be incomplete.
This volcano has existed for hundreds of thousands of years and during this time it has erupted at least 50 times, but its most famous activity occurred in 79 AD, when Pompeii was buried, and with them Stabiae, Herculaneum and some other smaller Roman cities. All of them were covered with a thick layer of volcanic ash.
As a result, about 2,000 people died (given the population density of that time, this is a lot), and the cities became uninhabitable for hundreds of years. Only in 1748, researchers discovered that the city of Pompeii was perfectly preserved under the ashes, which provided a lot of important information for studying the life of people of that time.
This eruption was preceded by a strong earthquake in the Campania region in 63. And according to the testimony of contemporaries of the event, a few weeks before the eruption, Vesuvius himself once again warned the inhabitants of the impending disaster, throwing a small column of ash into the sky. But this scared few people.
If the eruption of Vesuvius is repeated with the force that he is capable of, which is quite possible, it will threaten the lives of three million people who live in its vicinity. At the same time, a relatively small eruption of this volcano occurred in 1944, when 26 people died from the collapse of roofs under the weight of ash on them.
Lucky eruption – 1783
Iceland has a large number of volcanoes. This is due to the fact that it is located at the junction of tectonic plates. When small earthquakes or volcanic eruptions occur, the locals do not even worry. But sometimes more serious incidents happen. One of them was the eruption of Lucky.
It happened on June 8, 1783 in the south of the country. As a result, 2,500 square kilometers of territory was found under the lava layer, on which villages and even cities were located. This scale was achieved due to the fact that not one volcano erupted, but a whole chain of 135 faults. She got the name Lucky.
It only seems that volcanic ash is something soft and airy. A meter thick layer of such ash can crush a house.
The eruption itself did not do as much damage as its consequences. Ash and fluorine were carried over vast areas by strong winds. This not only polluted them, but also led to the defeat of a huge number of animals. Half of the livestock in Iceland and about a quarter of the horses and sheep were killed. The ensuing famine killed a fifth of Iceland’s population.
The products of the eruption hit the Gulf Stream and spread throughout the world. In Europe and the British Isles, many people have died from water and air poisoning. The climate also changed for many years due to the ingress of large amounts of ash into the upper atmosphere, which screened the sun’s rays. For several years, Japan and America have experienced terrible droughts and very cold winters. Many even say that it was the eruption and the ensuing drought, which in turn led to starvation, that provoked the French Revolution of 1789-1799.
Eruption of Krakatoa – 1883
This eruption was preceded by several aftershocks and ash ejections, which made people understand that this is the worst thing that can happen, but it was not. As a result, a violent eruption occurred on April 26, 1883. The explosion was heard thousands of kilometers from the volcano.
The speed of sound propagation in air is about 300 meters per second, or just over 1,000 kilometers per hour. That is, 1200 kilometers from the volcano, he was heard about an hour after the explosion. Just imagine this power!
The worst thing was that the eruption caused a tsunami, the height of which reached 40 meters. The tsunami on the coast killed 34,000 people.
You have to understand that Krakatoa is still an active volcano. However, it was that eruption that was the largest and since then something as serious has not yet been recorded. Moreover, the volcano is canonical. After each eruption, it increases, which leads to an increase in the strength of the following earthquakes.
Eruption of Novarupta – 1912
Novarupta is one of the chain of volcanoes in the Alaska Peninsula. The eruption of this volcano was the largest in the twentieth century. The eruption began on June 6, 1912. The explosion was heard even 1,200 kilometers from the volcano itself.
The eruption lasted for 60 hours, as a result of which 30 cubic kilometers of rocks and ash were thrown out. All this made dead many kilometers of land around the volcano. This became the largest volcanic disaster in the history of Alaska.
The first to realize that the eruption had occurred were the residents of the city of Kodiak, located 150 kilometers from the volcano. It was in the direction of this city that the ash cloud moved after it rose to a height of 30 kilometers. As a result, in three days the city was covered with a 30-centimeter layer of ash. It even led to the collapse of some buildings that could not support the weight of the ash.
People had to hide in their homes, as the city was completely plunged into darkness in 2.5 days. Local residents claimed that even the lantern was not visible at arm’s length.
The inhabitants of Kodiak Island, located about 150 km from the volcano, were the first to realize the seriousness of this eruption. The ash cloud quickly rose to a height of 30 km, and then approached them within an hour. Already a few hours after the eruption, ash began to fall on the island, for the next three days the thickness of the layer covering the city exceeded 30 cm.In 60 hours the city was completely plunged into darkness, it was difficult to see the lantern at arm’s length. Residents of Kodiak were forced to take refuge in the premises. Many buildings collapsed from the weight of ash on their roofs.
It sounds scary, but all this was still accompanied by earthquakes of magnitude up to 7 points and there were dozens of them (only recorded). The force of the eruption is also evidenced by the fact that about 5 cubic kilometers of rock in the mountain, which was a volcano, was destroyed.
Saint Helens eruption – 1980 eruption
St. Helens is one of the most active volcanoes in the United States. It was formed about 275 thousand years ago as a result of a series of eruptions. In recent history, the most powerful eruption was in 1980, when 57 people died, and damage was caused for tens of kilometers around.
During the eruption, a column of ash shot up 24 kilometers and covered 11 states to varying degrees. The worst thing is that during the eruption, the weakened rock slid off the mountain and made a landslide, rushing at a speed of up to 250 kilometers per hour. This led to the formation of a layer of stones and mud with an average thickness of 40-50 meters, but in some places up to 200 meters, formed along the 23 kilometers of the North Fork Toutle River.
Even today, there are traces of that eruption. For example, dead trees still drift in the Spirit Lake. In 2004, the volcano woke up again and erupted over 100 million cubic meters of lava, ash and rocks. And in 2016 there were about 130 small earthquakes, which confirmed the guesses of scientists about finding a large number of “pockets” of magma under the volcano. Her movement caused tremors.
Pinatubo eruption – 1991 eruption
A volcano in the Philippines, located about 100 kilometers from the city of Manila, Luzon Island, “gave a voice” on March 5, 1991. The first signs that something was wrong were a series of tremors. And already after, on June 12 of the same year, an eruption occurred, which lasted about one hour and generated a column of ash and gas about 20 kilometers high.
Three days later, the eruption was repeated in the form of a series of small “shots”. The result was a mushroom-shaped ash cloud about 34 kilometers high and about 400 kilometers in diameter. As a result of the eruption, about 5 cubic kilometers of ash were thrown into the atmosphere.
All this deprived of life an area of up to 400 square kilometers and covered the land around with a layer of lava up to 200 meters thick. In addition, with the rains, ash and other products of the eruption fell into the rivers, clogging them up. And the ash in the atmosphere, combined with suspended water droplets, circled the globe several times. This led to the fact that less sunlight reached the surface and the average temperature on the planet fell by 1 degree for a whole year.
Before the eruption, the volcano was an ordinary mountain, in the upper part of which there was a jungle. It hasn’t erupted in 400 years, creating a sense of seeming security. After the eruption, the mountain became lower by about 250 meters.
At the moment, the largest volcano is considered the one in Yellowstone Park. This place was formed due to a series of eruptions that took place many millions of years ago.
The last major eruption to date occurred about 640 million years ago. Then a thousand cubic kilometers of lava was sent into the air. It is not for nothing that it is called a supervolcano. The worst thing is that the volcano still exists and can erupt at any moment.
If this happens, then a catastrophe of a planetary scale may occur. About half of the United States will be under a multi-meter layer of ash, and the planet’s climate will change dramatically due to the huge amount of sulfur dioxide that will be released as a result of the eruption.
On the other hand, many researchers argue that the Yellowstone volcano will soon finally cease to be dormant and become extinct. They made this assumption based on the movement of tectonic plates, which does not lead to the formation of magma necessary for the eruption. So don’t panic for now. But if an eruption occurs, it may well lead to the death of all living things due to air pollution, water and soil throughout the planet.
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