The degassing process of the La Palma volcano can last for years

Image courtesy of the Geology professor and ULPGC researcher José Mangas of the La Palma volcano exclusion zone. / C7

The Geology professor at the ULPGC, José Mangas, attributes the slowness of this phase to the large amount of magma that cools under the island

Carmen Delia Aranda

The
degassing of the Cumbre Vieja volcanoon La Palma, is a long, almost desperate process, especially for residents who continue to be evicted from coastal neighborhoods such as La Bombilla or Puerto Naos due to the high concentrations of carbon dioxide and monoxide.

In total, between those who lost their homes under the lava flows and the people who have not been able to return to their homes due to the danger of the gases
there are about 1,600 people evicted, according to the calculations of the platform affected by the volcano of La Palma.

NOTES

  • Cause
    The large amount of magma existing under the island at more than 1,000 degrees Celsius cools down releasing gases

  • in the cone
    The fissures of the crater release gas emissions, especially water vapor together with carbon, fluorine, sulfur and chlorine

  • On the coast
    Carbon monoxide and carbon dioxide are heavy gases that accumulate at low levels

  • Risk
    In high concentrations, these gases displace oxygen, endangering the lives of people and animals.

«
This is going to be degassing for years», says the professor of Geology at the University of Las Palmas de Gran Canaria, José Mangas.

The expert attributes the slowness of the process to the large amount of magma still existing under the island, in the oceanic crust and upper mantle, with
temperatures that still exceed 1,000 degrees Celsius.

"This important volume will remain down there for tens of years in the conduits located at a depth of between 4 and 30 kilometers until the next eruption," says Mangas, who calculates that 4% of this volume of magma is gas. «
There is still a lot of volatility to come out», he says about the slowness of the degassing and cooling process.

Measurements in the volcanic cone

In his last forays into the volcanic edifice, the expert in crystallography and mineralogy found «
fissures that gave a lot of gas outlet, especially water vapor together with carbon, fluorine, chlorine and sulfur compounds».

near the crater what abounds is hydrogen sulfide, sulfur dioxide, hydrochloric acid and water vapor, as well as some carbon dioxide. These volatile hydrothermal vents continue to come out of fissures near craters and vents at temperatures below 400 degrees.

Nevertheless,
carbon monoxide and carbon dioxide abound in coastal areas associated with the eruption. «They are heavy gases, they accumulate at ground level in the valleys, in the galleries and at the bottom of the ravines because they are heavier than the air. That is why they are concentrating on the coastal area of
Puerto Naos and La Bombilla", He says.

"Instead of coming out of the upper part of the craters, the volatiles find fractures in the lower parts," explains the professor who suspects that these emanations could also occur in the submerged areas of the insular platform.

These small cracks are not noticeable. «We do not see them because simply the gases
they enter through small fissures depending on the porosity and permeability of the rocks. This allows the CO2 (carbon dioxide) and CO (carbon monoxide) that are in the inner magmatic chamber to come out”, explains this expert who directs a research group of the ULPGC with other national centers on hydrothermal minerals from the eruption of the palm tree. .

Invisible and odorless risk

The main risk that
the presence of carbon monoxide and carbon dioxide is that they are diffuse emanations that do not smell and can endanger the lives of people and animals because,
in high concentrations, it displaces oxygen.

"In some areas
dead pets and wildlife have been found. They are odorless and colorless gases that
affect the body unnoticed until you suffocate. You have to be careful », she warns.

normal parameters

The
seismicityscarce in the last days, is normal in a posteruptive process because the liquid mass of
magma has gases that are still looking for their way outr, argues the professor of geology.

In any case, the absence of ground deformation, tremor and seismic swarm
rule out the possibility that the magma will come out again.

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