80 days of activity are met for a volcano that will be, unless you stop by surprise this week, the longer since there are records in La Palma. They still surpass the first two eruptions with a known duration: that of Tehuya, in 1585, extension of 84 days; and that of Tigalate, in 1646, 82 days. Unfortunately, everything indicates that the record will be equal next Sunday.
If the evolution of a volcano is always unpredictable, the old summit has already given us all the imaginable samples to confirm this maximum. He has crossed cycles in which he seemed to lose strength to immediately reactivate, thus mining the hopes of the palm trees; He has surprised with an unusual parion, when he stopped for hours after a single week of eruption; And he has amazed the experts to explode, at the same time, ash by a mouth and lava on the other, as if there were two volcanoes in one.
"These geological processes, both earthquakes and volcanoes and even floods are very dynamic, very changing. We can prevent, but not to predict. Preaching does not exist, "says Pablo Gabriel Silva, professor of geomorphology and geological risks of the University of Salamanca. «And less with vulcanism. Vulcanism depends on many factors that are inside the earth and that they are unknown, "he adds.
"The equal volcano continues five months than tomorrow," illustrates. Is more: not only there are unknowns about what happens in the insides of the island, but it is also changing the floor of the palm, which accentuates the uncertainty about where the lava will fall and what constructions or crops will continue to destroy in its path . It is what happened, for example, with the cemetery of the spots, which seemed to have been saved until the cast 10 overflowed and ended up razing the camposanto.
"The volcano has generated castings that have changed the topography. The valleys have been filled out and the ravines have disappeared through which the castings could run, "says Silva. The new castings, explains, go down to the sea over the previous ones, sometimes about 20 meters high above the original terrain. "At the minimum there is an obstacle, an overflow occurs and another casting is generated." Therefore, it is increasingly difficult to foresee where the magma will go. "Any map of danger that existed before the eruption is obsolete, we can not trust him."
A peculiarity of the current volcano is that it has generated numerous ash feathers and pruloclasts and, at the same time, has expelled immense amounts of lava. In contrast, the two previous eruptions in the palm were mostly oropowned by a type of activity or another: Henugua, in 1971, was more explosive, with few cast, while that of San Juan, in 1949, expelled a lot of lava, but Little solid material, without leaving just volcanic building.
The new eruption, however, has combined the worst of the previous two: "Magma is leaving the same, it is supposed to be of the same reservoir, the same chamber, but by some areas is dating explosive activity and for the mouths of Below is coming out with effusive activity, which is the one that feeds the castings, details Silva. "It's almost the first time you see that."
It also caused confusion the strange seven-hour pause that took the volcano on September 27. "He created a huge bewilderment, because it was very soon. Represented the worst scenario of all possible: that there is a reopening or a reactivation of the volcanic process, but not in this volcano, but in a new one, which could be kilometers away; It was the worst thing that could happen, "recalls Vicente Soler, representative of the CSIC in the scientific advisory committee of the pebolca.
"Fortunately, it was not like that," continues this expert, but the case illustrates perfectly that "we move in an atmosphere of permanent hypothesis." In contrast to the rocks and gases that expel the volcano, which can be analyzed in detail, "the processes of the interior of the Earth are not directly accessible, of any of the ways," Exhibits Soler.
"When we talk about surface measurements, there is great precision, there are all kinds of instrumentation. When we talk about the processes in depth, we sponsor indirectly with the seismic, the seismic waves that go through the subsoil, and the deformation that occurs by the magmatic thrust », details soler. "But little more is what can be said. The difficulty of talking about these things is great and the ability to make mistakes, too, "he adds.
Are we only at the expense of what the volcano wants? "At the expense of what the volcano watched and at the slow progress of the sciences of the Interior of the Earth," Soleler responds, who concludes with the following comparison: "The astrophysists, as they analyze the light ... because it is more than known. A star in the confines of the galaxy than from the inside of our own planet ».
Date Of Update: 07 December 2021, 23:35
