The seismic activity that began to register a few weeks ago on the island of La Palma, with thousands of small earthquakes, has finally caused the eruption of one of the volcanoes on the Canary Island, the one located in Cumbre Vieja. An eruption that began this Sunday at 3:12 p.m., after feeling a small earthquake in the town of El Paso, and which was followed a tremendous explosion and a huge column of smoke. The fissure-type eruption has opened at least seven eruptive mouths that emit rivers of lava and from which pyroclasts of different sizes are expelled to the surface.
The big question that everyone is asking now is what the evolution of the eruption will be and, above all, how long it can last. Experts point out that “it is still too early to know”, since it depends on both the eruptive dynamics and the amount of magma that the volcano harbors. “The eruptions in the Canary Islands they usually last weeks, but could last for months “, explains to EL ESPAÑOL Itahiza Domínguez, a seismologist from the National Geographic Institute (IGN).
The main impediment to knowing this data is that it is unknown exactly how much lava is inside. At first, there was talk of 11 million cubic meters, a lower quantity than the Teneguía, the other volcano on the island that erupted 50 years ago, in 1971. Inside it housed 43 million cubic meters of magma and the eruption lasted for 24 days. “Actually, those 11 million are not all the volume that is in the interior. There is more magma underneath and it can rise to the surface through the generated conduits,” says Domínguez.
The seismologist points out that the next 24 or 48 hours will be key to know the evolution of the eruption. “The explosiveness of the eruption may change slightly at the beginning and you have to be vigilant in case new fissures open. For now it seems that not, but it is still early. These eruptions can evolve rapidly, with the appearance of new fissures and causing the exit of material with certain explosiveness “, he points out. This is also confirmed by Stavros Meletlidis, volcanologist from IGN to EL ESPAÑOL, who assures that the mouths that are opening “are unpredictable” and, depending on the amount of gases inside, they can open more “or erupt several at the same time, as now.”
Experts point out that, despite the spectacular images, the eruption is not being violent. “The eruptions in the Canary Islands are quiet eruptions compared to those that occur in countries like Indonesia, which generate 20-kilometer ash plumes.” In this case, it is a strombolian-type eruption (named after the famous Italian volcano), with “few explosions that emit pyroclasts.” An eruptive dynamic that resembles that of Fagradalshraun, the Icelandic volcano that has been erupting for six months and has already expelled 143 million cubic meters of lava.
In addition to pyroclasts and lava tongues, experts warn that the volcano is also emitting toxic gases, mainly carbon dioxide and sulfur dioxide, which can become dangerous if someone approaches the area and inhales them. In fact, the only person who died during the Teneguía eruption 50 years ago was due to the inhalation of one of these gases. “Carbon dioxide is a gas that cannot be smelled and causes you to pass out and end up dying from lack of oxygen. Sulfur dioxide is also poisonous in not too high concentrations, but as long as no one approaches, gases are emitted into the atmosphere and do not generate any danger. There are eruptions that generate much more sulfur dioxide and do not affect people as long as they are not around, “explains Domínguez.
What happens in the next few days on La Palma is still unknown and will largely depend on the eruptive dynamics of the volcano. “Once the eruption starts, there is not much margin. best scenario that could happen is to stop as soon as possible, obviously, and produce the least possible material damage “, predicts the seismologist. However, the opposite can also happen, that the eruption is maintained over time and the ash column could affect the air traffic of the island.
“Once the area where the eruption takes place is known, there is practically no danger for the population. There is material danger, that is inevitable, due to the lava tails. There will also be small fires, but for the population there should be no danger” , Domínguez ends.
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