“We should have been worried if they had not erupted.”
The Earth, as if responding to the actions of its restless inhabitants, frightened us with the eruption of lava from several volcanoes at once. First, on November 1, the Kamchatka volcano Klyuchevskoy threw ash to a height of 14 kilometers, on Monday night the Sicilian Etna (4.5 km) woke up and, finally, everyone is waiting to see if two volcanoes in Iceland – Reykjanes and Fagradalsfjall – will “break through”. We learned about the true reasons for such activity of the earth's interior from the Russian volcanologist Ruslan Zhostkov.
The highest volcano in Eurasia, Klyuchevskoy, began its summit eruption back in June of this year. On November 1, it reached the paroxysmal (sharply aggravated) phase – the ash column during one of the emissions reached 14 kilometers in height. Fortunately, the wind carried him away from the villages of Bezymyanny and Klyuchevskoy.
According to employees of the Institute of Volcanology and Seismology of the Far Eastern Branch of the Russian Academy of Sciences, such paroxysms happened to Klyuchevsky in 1945 and 1994. As a rule, they last 5-10 hours, after which volcanic activity subsides. This is what happened this time too – having melted the glaciers and caused mud flows that washed away one of the highways, Klyuchevskoy is gradually calming down.
However, his baton was “picked up” by the Sicilian Etna. According to the National Institute of Geophysics and Volcanology of Italy, cited by the newspaper La Sicilia, the unexpected eruption of lava began on Sunday, November 12. It formed a column of gas, ash and volcanic rock debris that rose to 4.5 kilometers above sea level. In this case, volcanic ash nevertheless covered two populated areas – the cities of Giarre and Riposto, after which the volcano, to whose vagaries the locals had long been accustomed, calmed down quite quickly. The local authorities did not even have to close the local Catania airport, as was the last time in March 2017.
Now let's move to the Icelandic town of Grindavik, located on the Reykjanes Peninsula. More than three thousand residents and tourists of this town were evacuated on Saturday in anticipation of eruptions of the Reykjanes volcanoes (of the same name as the peninsula) and Fagradalsfjall. A state of emergency has been introduced in the region; there is a forecast that Grindavik may be partially destroyed.
Reykjanes was the first to make itself known, in whose area a series of tremors were recorded. The head of the Icelandic Emergency Management Agency, Vidir Reynisson, said that they were caused by the displacement of magma underground, this indicates an approaching eruption.
The situation is complicated by the fact that not far from the volcano there is a geothermal station Svartsengi, which generates electricity for several tens of thousands inhabitants of the peninsula. The eruption of both volcanoes, according to Reynisson, is expected within a time period of several hours to two days.
According to Ruslan Zhostkov, a senior researcher at the Laboratory of Fundamental Problems of Environmental Geophysics and Volcanology at the Institute of Earth Physics of the Russian Academy of Sciences, the events described above are absolutely unrelated.
– As for the Kamchatka volcanoes, such as Shiveluch and Klyuchevskoy, this is a zone subduction, “the giant Pacific plate goes under the continental plate,” explains Zhostkov. – As rocks sink into magma, they melt and come to the surface. Shiveluch erupted in April of this year, after which the activity shifted south, to Klyuchevskoye.
Etna is also generated by a subduction zone, but between the African and Eurasian plates. It erupts more often than Klyuchevsky: if he does this once every two years, then Etna can throw out volcanic ash several times a year.
Icelandic volcanoes have a completely different genesis. They are the result of the activity of a plume, a jet of magma that stretches from the outer core of the Earth, passes through the entire mantle and burns through the earth's crust, bringing energy and mass to the surface. This is a very powerful source, one of the hottest, in the literal sense of the word, spots on the planet. I consider the evacuation of the residents of Grindavik to be very timely: the number of earthquakes there is now huge, it is difficult to predict what scale the eruptions will be.
In general, according to Ruslan Zhostkov, the almost simultaneous eruption of three or four volcanoes in different parts of the Earth – this is a normal, normal mode.
“You should be worried if they didn’t erupt, didn’t release excess pressure,” says the scientist.
The last time is the most A powerful volcanic eruption on Earth, reaching the highest 8 points on the scale of volcanic activity, occurred 27 thousand years ago on the North Island of New Zealand. It was caused by the Taupo volcano, which ejected 1,170 km³ of volcanic material that reached a height of more than 20 kilometers.
Such mega-eruptions occur no more than once every 10,000-50,000 years, significantly affecting the climate of the entire Earth. As for the Eyjafjallajökull volcano, which erupted in Iceland in 2010, it reached only 4 points.
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