The thousand faces of the La Palma volcano: why the eruption is still far from stabilized

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A constant roar and a lava that does not stop sprouting. After 12 days of eruption, the lava material from the volcano has already created a low island at least half a kilometer wide. A strip of 10 hectares that will continue to grow as the magma expelled by the volcano runs through the southwest of La Palma until it empties into the sea. Not without first destroying in its wake what experts already estimate at 476 hectares and 855 buildings. The risk is high and, from the Canary Islands Civil Protection (Pevolca) they warn: the rash is not stabilized.

The effusive phase of the Cumbre Vieja volcano continues to eject material to the surface. The main cone emits mainly pyroclasts and ash, and just below, a younger, less viscous and faster magma flows through a secondary opening with the pretense of continuing to flow into the sea. So far, up to 46.3 million cubic meters of lava have been expelled. A figure that will not stop increasing in the coming days taking into account that the volcano is in full effusive phase, with a continuous emission of material.

And as long as the magma continues to escape to the surface, the huge column of smoke and ash that has been clouding the sky of La Palma for almost two weeks will not stop either. The plume continues to emit tons of carbon dioxide (CO2), sulfur dioxide (SO2) and other gases. The column reaches in the last hours the 5,000 meters of altitude and has increased the daily emission of SO2 up to 10,757 tons.

María José Blanco, spokesperson for the Pevolca Scientific Committee, reported this Thursday that the meteorological conditions forecast in the coming hours will cause the ash cloud and SO2 to affect mainly to the west side of La Palma, and will be unfavorable from the point of view of air quality. However, the limits higher than 500 micrograms per cubic meter of sulfur dioxide that are occurring in areas such as Tazacorte do not pose a health hazard.

On the other hand, the wind is lower than in the previous days, which is creating a sensation of a greater presence of ash on the island. The gusts of wind these days seemed to direct the ashes towards the ocean. But in the last hours, as reported by the Cabildo de La Palma, up to 1,700 hectares of the beautiful island covered by ash. A material that, they say, will be collected for later use in road construction and as fertilizer in agriculture. As we explain in EL ESPAÑOL, their composition in minerals and other substances makes them an ally for the sector.

The most likely scenarios

The experts consulted by this newspaper they shuffle various scenarios, but all agree that the best and most probable is that, while the eruption lasts, the lava will follow the same path and flow into the sea. This is what Alicia Felpeto, a volcanologist at the National Geographic Institute (IGN) assures, that “the best scenario is that it continues like this, that it continues to discharge the lava into the sea and gain ground. It is the scenario that would have the least impact on the population” .

The lava, for the moment, continues its path, the same one that opened last Monday when the magma began to come out through the second fissure of the volcano. However, the probable scenarios also include others such as the current runoffs that may open other crossings. “It could happen that they widen a little more,” adds Felpeto. The expert points especially to the wash in the southern area that surrounded Montaña Rajada, “or one that seems to aim to go through the northern area of ​​the Todoque mountain as well. That would be expected.”

Therefore, it is not ruled out that the streams widen horizontally and even take another route on their way to the sea. Felpeto also describes another probable scenario, and that is that “solidified sides of lava can sometimes break and another wash may come out which, depending on the topography it finds, may affect new areas of the territory or may rejoin the main one “.

Lava, depending on its viscosity and temperature, you can change your address and it is not ruled out that it can expand laterally from the main casting. For this reason, what most worries the experts at the moment are the sudden changes of the eruption.

What do the latest earthquakes mean?

The scenarios are multiple and most of them unpredictable. The experts ask for patience and time to analyze the information that the volcano reveals as the days go by. Their predictions are based on the antecedents of other volcanoes and on the analysis of the signals that the volcano shows.

Among those signs is the seismic swarm that has been shaking the south of La Palma since the eruption began, but which in the last hours seems to have intensified. As reported by the IGN, the volcanic tremor – that continuous signal emitted by the erupting volcano – remains stable, but up to 21 earthquakes have been detected between 9 and 14 kilometers deep. Some of them, higher than a magnitude three that have come to be felt by the population, and especially in the areas of Fuencaliente and Mazo.

“Earthquakes are occurring at a certain depth and of a significant magnitude,” says Jesús Ibáñez, a seismologist at the Andalusian Institute of Geophysics. Both for him and for his volcanic research group deployed in the area, the earthquakes experienced in the last hours show a scenario that implies a new injection of magma from the mantle – about 20 kilometers deep – towards the surface.

As the expert explains, when there is an earthquake at that depth it is that magma is rising and is on the edge of the oceanic crust. “It is where the crisis occurred six months ago and indicates that it is where there is the greatest volcanic injection,” he points out, “which would lead to a lengthening of the eruptive process.” However, he points out that another probable scenario is that if this magma does not generate a pressure greater than that of the surface, it would stop coming out and the eruption would end.

Felpeto points out that “seismic activity is constant” and earthquakes that are felt by the population continue to be recorded every day. The researcher assures that these signals can indicate various issues, including the opening of new fissures, new mouths or the rise of magma, among others.

In this sense, Vicente Soler, a volcanologist from the Higher Council for Scientific Research (CSIC) explained through his networks that “if another mouth is opened” where lava is expelled, the most logical thing is that he would do so “on the previous one” but “he would have to find his way again”, which would be a worst case scenario.

There are also other scenarios, but that experts point out as very unlikely, and it is, for example, that the situation arose in which the magma came out from another place and moved. “We would have a new eruptive scenario,” says Ibáñez. Likewise, it could also happen that it interacts with the water in depth and increases the explosiveness of the eruption. However, “La Palma’s eruptive history does not show serious explosive scenarios and that scenario is extremely remote. It’s the last thing that could happen, “he says.

“Although there are those who have said that they would have preferred an explosive eruption, the more effusive it is, the less damage it causes,” says the expert. As he explains, if all this effusive material in the form of lava flow were released through an explosion, “we would be talking about a completely devastated territory”, but this, he emphasizes, “is impossible”.

Nevertheless, the most probable scenarios remain in the continuous emission of lava towards the sea, either through the same path that it has been traveling since Monday, or through the possibility of new washes being opened. For this reason, the vigilance of the situation is maximum because it can change from one moment to another.

Rubén Fernández, technical director of Pevolca, has announced that the maritime and land exclusion zones will be maintained, the evacuation of the neighbors decreed last week and the confinement of the population centers of San Borondón, Marina Alta, Marina Baja and The Countess to ensure your complete safety. As he pointed out, they are conducting “studies and constant monitoring, and until we know that these areas are out of risk, these measures will be maintained.”

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