Saturday, January 22

The La Palma volcano falls into an eerie silence with signs of exhaustion

Be quiet. The La Palma volcano he has stopped complaining, though he is not breathing yet. The guttural roars that during 87 days have accompanied the palm trees have suddenly ceased, after a great last lament that some scientists believe could have been “the final fireworks”. The great cone that lava has built for almost three months no longer releases gases, or ashes. Neither does it wash.

The stillness is such that even the birds dare to cross the place. Now it is only a few vents on the sides of the cone that emit some smoke. A reminder that there is still a giant under the earth. Therefore, calm cannot yet be a sign of the end. Scientists at least do not consider it that way, since it would not be the first time that the volcano has insisted on deceiving the population with its calm and later reviving with much more force. However, for the first time on Tuesday, researchers from the Pevolca Scientific Committee ventured to say that there are signs of “exhaustion of the eruptive process”.

And it is that the volcanic activity has diminished “until almost disappearing”. This was highlighted by Miguel Ángel Morcuende, technical director of Pevolca, who alluded to the main eruptive indicators such as seismicity, deformation and the emission of gases. Of all of them, the one that stands out above is the end of tremor. The signal emitted by the lava when it hits the walls of the conduit has been one of the clearest when it comes to understanding the phases that the volcano was going through. On the same Monday, the signal went off for a few hours (from 5:45 p.m. to 7:00 p.m.), coinciding with one of the most explosive moments that the volcano has had since the eruption began. A large lava torch erupted again from the main focus accompanied by a large amount of ash ejection – which turned into thick rain overnight – and bomb drops, especially on the north flank.

After this episode, the volcano fell asleep, as well as the tremor that began to decrease from 8:00 p.m. on Monday. So from 22:00 on that day it is at background noise levels, which means that its silence is similar to what it was before the eruption began. This reduction in noise has also made it possible to start registering the smallest earthquakes. Thus, in the last two days there have been fifty earthquakes with a magnitude less than 2. The minimum magnitude of these earth movements has been 1.1 mbLg. For its part, the maximum magnitude recorded is 3.4 mbLg, corresponding to an earthquake on Monday at 11:58 am, which occurred at a depth of 11 km and was felt very slightly. Most of these events (125) are located at intermediate depths, between 8 and 16 kilometers, but this does not mean that the deepest seismicity has completely subsided. According to the National Geographic Institute (IGN), only three earthquakes have been located at depths between 37 and 49 kilometers. Also noteworthy is one of low magnitude (1.4) but that has occurred near the surface, just 3 kilometers away. Despite the current data and the calm, the Scientific Committee has warned that it is possible that more felt earthquakes may occur, reaching intensities higher than those of the last days.

Regarding the deformation – an index also relevant to know the eruptive situation – it does not show no clear trend near the cone, while in the rest of the stations the slight deflation possibly related to deep seismicity has stabilized, except in station LP01, which continues to register a deformation.

With regard to gases, the Canary Islands Volcanological Institute (Involcan), which is the body in charge of carrying out the plume measurements, points out that the levels of sulfur dioxide (SO2) are still “high”, which means which is in a range of between 1,000 and 29,000 tons. In the case of the diffuse emission of carbon dioxide (CO2) it continues to reflect an emission higher than the average value of the background levels (B) and during Monday (12/13) this diffuse emission was 7.9 times the average of background levels. These emanations, which are higher than other weeks, can represent a danger to the population in the Bulb area, especially in poorly ventilated places or at altitudes below one meter above the ground, as a consequence of the possible accumulation of carbon dioxide.

With regard to air quality, SO2 levels remained good in all seasons, after the episode recorded last Monday where the situation was extremely unfavorable in the Aridane Valley and forced to confine three municipalities for a few hours and more than 32,000 people, including children who had to spend several hours locked in their classrooms.

Even if La Palma volcano lava does not emanate abruptly from the cone, the lava flow continues from the western base from the main cone, from volcanic tube leaks and up to the lava delta formed in the sea, although with a much decreased flow compared to yesterday. In the lava delta of the Las Hoyas area, the wash runs over previous lavas without new contributions to the sea. In this regard, Miguel Ángel Morcuende pointed out that the contributions of lava are very weakened and flow mainly through the southwest of stream 9, with small spills in Montaña Cogote and Las Norias, where the thermal cameras show greater residual heat.

After 87 days, the area buried under the incandescent lava of the volcano already amounts to approximately 1,195 hectares, while the flows have expanded more than ever in an eruption on La Palma: 3,350 meters. For its part, the land reclaimed from the sea thanks to the lava deltas amounts to 48.02 hectares. The devastation of the volcano, according to the Cadastre, has ended with 1,628, a figure that amounts to 3,063 according to data provided by the Copernicus satellite. The evacuation of more than 7,000 people whose residences are located in the exclusion zone still means that many have had to stay in hotels on the Island. housed in hotels amounts to 551 people, which is five more than on Monday. Of the total, 395 are staying in Fuencaliente, 69 in Los Llanos de Aridane and 87 in Breña Baja, managed by the Red Cross and municipal services. In addition, there are 43 dependent people cared for in insular health centers.

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