José Manuel NievesSEGUIRMadrid Updated: Save Send news by mail electrónicoTu name *
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Many volcanoes produce the same types of rash during long million years. This is the case, for example, volcanoes in Iceland, Hawaii or the Galapagos islands, whose eruptions consist always in lava flows, made of basalt rock melted, forming long rivers of burning on its slopes. Something that, by repeated, it is predictable and hardly cause concern among neighbors and authorities.
it Is true that these lava flows are potentially harmful to the buildings nearby, but generally move so slowly (at strolling pace), that they represent a risk. Something very different from what happens with the so-called “explosive eruptions” , much higher, as the Vesuvius or mount Santa Helena , able to surprise to whole populations and cause a sudden large number of casualties. Far from it, the limited activity of these volcanoes relatively quiet gives the locals a sense of confidence that leads them, even, to bring tourists to see the lava flows when they occur.
A trust, however, that could be misleading. An international team of volcanologists working in the Galapagos islands, in effect, just discover that this multitude of volcanoes “predictable” and that always produce the same small eruptions of basaltic lava hidden in their systems of underground pipes magmas of varying composition, including some with the potential to generate explosive activity. The work has just been published in Nature Communications.
The danger lurks under the volcano
The team of researchers, led by Michael Stock, Trinity College Dublin, and composed of scientists from EE. UU., Uk and Ecuador, studied two volcanoes of the Galapagos during their whole existence only to have erupted lava flows basalt of uniform composition. But by analyzing the compositions of microscopic crystals in the lava, volcanologists were able to rebuild the physical and chemical characteristics of the magmas stored in the subsurface, beneath the volcanoes.
Surprisingly, the results of the study show that these magmas are stored beneath the two volcanoes are not composed only by the basaltic lavas that both spill over the surface, but also include compositions that are very similar to those emitted by mount St. Helens during its violent explosive eruptions.
the researchers believe that the uniformity observed in the eruptions occurs when the amount of magma flowing beneath the ground is large enough to “overprint” any chemical diversity. Something that can happen when volcanoes are found near a “hot spot”, that is to say, of a column of magma very hot rises towards the surface from the depths of the Earth.
however, the researchers believe that, in certain circumstances, the magmas chemically diverse discovered by the computer could become mobile and move towards the surface. If it were the case, those volcanoes that have been spewing only basaltic lava millennium after millennium could suffer unexpected changes and show an explosive activity so much more dangerous.
In the words of Stock, the finding “it was totally unexpected. We started the study wanting to know why these volcanoes were so boring and what process did that the compositions of lava in eruption were to remain constant over long periods of time. In contrast, we find that we are not boring at all, just hide these magmas secrets beneath the earth”.
“Although there are signs that these volcanoes of Galapagos will undergo a transition in the style of their eruptions in the short term-continues the scientist-, our results show why other volcanoes could have changed his behavior eruptive in the past. The study also will help us to better understand the risks posed by volcanoes in other parts of the world. The fact that you always have erupted in a particular way in the past does not mean that you trust them, or will keep doing the same thing indefinitely into the future”.