” If an eruption of this magnitude had occurred on earth, I am thinking of Vesuvius or Campi Flegrei, the consequences would have been apocalyptic ”. Thus the German volcanologist Boris Behncke, researcher at the National Institute of Geophysics and Volcanology at the Etneo Observatory in Catania, comments with Adnkronos on the eruption of the underwater volcano Hunga Tonga-Hunga Ha’apai, in the Tonga archipelago in the Pacific Ocean . ” Unfortunately, the luck was that such an eruption occurred in an extremely remote and sparsely inhabited area – he says – If it had occurred on the ground in a populated area, it would not have caused a tsunami, but would have caused devastation even from a distance. several kilometers ”.
However in Tonga ” the eruption, which had very serious consequences on the neighboring islands, was probably amplified in its violence because it occurred at the interface between the sea and the atmosphere. An entire island, which had formed 6-7 years earlier and which had grown right before the explosive activity, was destroyed. ” The positive aspect of the eruption, “very fascinating from a scientific point of view”, is “the surprisingly low number of human lives”, of victims. In addition to the fact that these are sparsely populated islands, it is also due to the ” highly trained inhabitants. Although they have no memory of a similar volcanic eruption, they have seen very strong earthquakes, cyclones, hurricanes, tsunamis. So they immediately fled to higher areas, they clung to the trees … ”.
Another problem, now, is given by the presence of ” ash that can derive from the eruptive cloud and contains potentially toxic substances. When the ash settles on the earth, as happens with Etna, it is washed. But in Tonga the situation is made more complicated by the deposit of ash in the sea, which contains sulfur, chlorine and other substances ”.
It is difficult, however, to imagine an eruption of a maritime volcano similar in scope to that of the Tonga in the Italian seas. ” I don’t expect such a violent eruption of an underwater volcano in our seas, ” says Behncke. Citing Marsili, the largest submerged volcano in Europe and the Mediterranean located in the Tyrrhenian Sea between Palermo and Naples, Behncke explains how it is located at “ a very great depth ” compared to the Tongan volcano and how “ the pressure of the column of water largely suppresses its explosive energy. ” From the volcano that erupted in Tonga, however, “it cannot be excluded that it will still erupt”, because already “in the past, about a thousand years ago, it recorded a similar, very violent eruption. It therefore seems cyclical ”.
But the violent eruption of the Hunga Tonga-Hunga Ha’apai underwater volcano will not affect the global climate because “ the amount of sulfur dioxide injected into the stratosphere ” after the eruption was too small to have an appreciable impact on the global climate. and to produce a ‘cooling’ of temperatures. After a large volcanic eruption, he explains, “ there can be a cooling in one or two years of a tenth of a degree centigrade ”. It happened for example “in 1991 with the eruption of the Pinatubo volcano in the Philippines, one of the largest eruptions of the last century”. On that occasion there was a ” very important diffusion of sulfur dioxide ”, while that introduced into the stratosphere by the Tongan volcano is not sufficient to have an appreciable impact on the global climate ”. The quantity of sulfur dioxide emitted by the Tongan volcano is “forty times lower” than that of the Pinatubo.
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