Monday, November 28

How we know that the La Palma eruption has ended: scientists provide the keys and what we can expect now

Eighty-five days and eight hours later, a whole “volcanic autumn” In the words of the Canarian authorities, the residents of La Palma breathe a certain relief. Julio Pérez, Minister of Public Administrations, Justice and Security of the island Government, came to the fore on Saturday with the most anticipated news in the archipelago: Experts consider the eruption in the Cumbre Vieja area to end, which since September 19 has kept the palm trees gasping for air, has forced 7,000 people to evacuate and generated 1,219 hectares of lava.

The announcement – the Canarian high official recalled – comes exactly ten days after the end of the eruptions was confirmed, on December 13. “There are no pyroclasts, there are no significant earthquakes”, he stressed. The key to the day after is: What are the experts based on to claim that the eruption is over? And, above all, what can we expect from now on?

Relief, but with caution

The main evidence – as Pérez himself detailed on Saturday – is the ten days established by the Scientific Committee as margin necessary to terminate the eruptive process, a period that began to run on December 13 at night (22.21 h). The body, coordinated by the General Directorate of Security and Emergencies of the Government of the Canary Islands and made up of the IGN, CSIC, Involcan, IGME, AEMET, IEO and the universities of La Laguna and Las Palmas, concluded that after that period the observations, both direct, on the surface, as through surveillance systems, have corroborated “The exhaustion of the eruptive process” started in september.

There is no presence of volcanic tremor in the seismic signals. Seismicity, which is of low magnitude, is at very low levels at all depths ”, the committee abounds in a note distributed by the Canarian Government. Other indicators are the “exhaustion” of the process itself, the low seismicity and the “deformations without tendencies.” The ten days of margin set by the scientists to assess the signals have, however, been much more than a mere formality.

As María José Blanco, from the National Geographic Institute (IGN) explains, to the EFE Agency, the tremor, the vibration generated by the displacement of magma to the surface, disappeared just a day after a phase of great explosiveness. Volcanoes like San Juan, in addition, they reactivated after several days of standing, which advised to act with “caution”.

Does that mean that the risk has disappeared? Both those responsible for Pevolca and scientists are clear: certain risks still persist. In fact, they ask the population of La Palma not to lower their guard. “The end of the eruption does not have to imply the end of some dangers associated with the volcanic phenomenon, nor necessarily the end of the magmatic reactivation in Cumbre Vieja”, warn from the National Geographic Institute. Furthermore, despite the fact that the latest seismicity data point to a “low magnitude” and “it is at very low levels at all depths”, it recognizes that “the occurrence of felt earthquakes is not ruled out.”

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Blanco points out that the degassing of the washes it will still take “weeks” to finish and the total cooling will still take “months”, a period that could be “even longer” at those points where the thickness has been exceeded 50 meters. In your report yesterday, the scientific committee also warns that diffuse emissions of carbon dioxide (CO2), such as those detected on Friday, “may pose a danger to people in some areas from the Cumbre Vieja volcano ”. Experts specifically target poorly ventilated areas or at ground level.

After the volcano: how and when will we recover what the La Palma eruption has destroyed

From the Government of the Canary Islands share the message of caution. Although Pérez himself acknowledged on Saturday receiving with “relief” – “It is not joy, I cannot say that we are happy, and neither is satisfaction”, he acknowledged – the end of the eruptive process after verifying the end of the tremor, the low magnitude of the seismicity and the absence of lava and ash, added that the emergency has not ended. The Pevolca, in fact, remains on a red light. “Surveillance and monitoring will continue throughout the area, but we will start from Monday to study the rehousing plan,” he explained.

Cover image | Tanya Grypachevskaya