Sunday, October 17

The seismic swarm of La Palma resurrects the old theory of a megatsunami over the US due to the collapse of a volcano


The seismic swarm that shakes La Palma has revived an old theory that predicts that an eruption in the volcanic building of Cumbre Vieja would unleash a megatsunami in the eastern United States. The Volcanological Institute of the Canary Islands (Involcan) dismantled this hypothesis in 2017, but the expectation about the tremors that are happening on the beautiful island these days has rekindled the debate among the population and on social networks. ” For the Cumbre Vieja flank to meet conditions close to instability, an earthquake of very high magnitude would have to occur simultaneously along with an eruption with a high explosivity index, or the current volcanic building would have to reach in its natural growth at least more than a thousand meters above the current maximum elevation, “said Involcan. For the volcano to reach this height,” more than fifty thousand years would have to pass. ”

Scientists note a decrease in earthquakes in Cumbre Vieja, but the deformation of the ground rises to 10 centimeters

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The defenders of this hypothesis emphasize that La Palma is a “volcanic and unstable” island. Steven Ward, professor at the Institute of Geophysics and Planetary Physics at the University of California, and Simon Day, from the Benfield Greig Hazard Research Center at the University of London, published the research in 2001. Cumbre Vieja Volcano, potential collapse and tsunami at La Palma. “Geological evidence suggests that in a future eruption, the Cumbre Vieja volcano on the island of La Palma could experience a catastrophic collapse on its west flank, throwing between 150 and 500 cubic kilometers of rock into the sea,” the document says. .

According to the analysis, the collapse of half of this Canary Island in the Atlantic Ocean would cause a tsunami that would hit and flood the city of Bristol, in England. The fall of this piece of land on the sea would create a wall of water that would advance “faster than an airplane.” It would hit the coast of Portugal, of peninsular Spain and, in a few hours, it would reach England and the United States. The waves, between 10 and 25 meters high, would destroy the south of England and would reach the North American coast.

This theory has even become the story line of different books. Among them, that of the Madrid writer and archaeologist Hipólito Sánchez. His work Interitum Mundi. When the world cried for the last time It has apocalyptic overtones and begins in the Canary Islands. In it, he recounts how La Palma fragments and falls into the sea. The collapse of the volcanic building in the south of the island ends with a tsunami that devastates the east coast of the United States.

A business for insurers

“It may happen tonight or 2,000 years from now, but it will happen, it will happen, unfortunately,” said the writer in an interview with this newspaper. “North American satellites monitor the Canary Islands day and night, and especially La Palma, in the face of the possibility of a tsunami that would devastate the entire east coast of the American continent.” According to the archaeologist, the consequences would be “catastrophic” and insurance companies are already taking advantage of this forecast: “They have done a great business with this issue.”

The relationship between the authors of the 2001 study and. insurance companies has also been collected in various studies and analyzes on the theory of megatsunami. Steven Ward is part of the Institute for Geophysics and Planetary Physics at the University of California. Meanwhile, Simon Day is a member of the Benfield Greig Hazard Research Center. This center is in London and brings together geologists, meteorologists and specialists in natural disaster management, but it is also attached to the Benfield Group insurance group.

The book Landslides, tsunamis and volcanic crises, written by Eustaquio Villalba, includes some statements from the head of the Department of Volcanology in the Canary Islands of the Higher Council for Scientific Research (CSIC), Juan Carlos Carracedo. In them, the scientist argued that it was “interests linked to insurance companies” that sowed fear of a tsunami.

Canary Islands, stable islands

The Volcanological Institute of the Canary Islands and several renowned experts who belong to it, such as the Spanish geologist Luis González de Vallejo, have defended the stability of the volcanic building of Cumbre Vieja on more than one occasion. In a recent study published in 2015, Vallejo and other scientific colleagues from the Geological and Mining Institute of Spain conclude that, taking into account different future scenarios, such as an intrusion of magma or earthquakes, none of them would cause the collapse of the volcanoes of Cumbre Vieja and El Teide, the another volcano analyzed.

“These results show the current stability conditions for the islands studied, showing their stable conditions against large flank faults.” In the case of Cumbre Vieja, Vallejo explained that there would be instability if the volcano grows more than a thousand meters. But to reach this altitude “it would take more than 50 thousand years, taking as a reference the average growth rate of the island in the last half a million years.”

In the Canary Islands, explains the scientist, there have been large displacements that have resulted in megatsunamis, as he and other academics describe in an article published in August this year. However, these phenomena have occurred because growth has been very rapid on a weak soil base, which tends to give way due to lack of stability.

In addition, one of the backbones that support the theory of a collapse of Cumbre Vieja, as well as the subsequent tsunami, is based on the existence of surfaces of geological weakness of great extension, continuity and depth. Along with this, there would also be, according to the study by Simon Day and Steven Ward, an almost vertical fracture tens of kilometers long and several kilometers deep. The latter, in the words of Involcan, has not been verified. “Cumbre Vieja would be stable according to the geomechanical models and stability analysis carried out.”

A media tsunami

The hours of television that the hypothetical tsunami caused by the collapse of Cumbre Vieja has been uncountable. And the story, in the head of each of the canaries without even knowing why, has a starting point. He was born in 1999, with an interview from the BBC Simon Day and a documentary a few hours later about this presumed catastrophe. In Spain, a few months later, the news was echoed by the newspapers The world, with an article titled Will La Palma explode? The canary apocalypse, and the ABC.

Quickly, according to the geographer Eustaquio Villalba in his book Landslides, tsunamis and volcanic crises (2015), the political class singled out Simon Day for trying to “sink the tourism industry” with these catastrophic predictions. The controversy began to rise little by little and the Canarian scientific community immediately passed. One of the best known geologists at the time, Telesforo Bravo, refuted Day’s conclusions and even joked that he was going to buy a surfboard to take advantage of “such a magnificent wave.”

But the media wheel kept turning. First the BBC, then he National Geographic, whose name of the documentary was End day (The last day), the channel History and even the series CSI Miami, which devoted a chapter to the alleged devastation that would occur in Florida by the tsunami. The British newspaper The Guardian, In 2004, he summed up this whole story in a very eloquent headline: A Hollywood fantasy? The tsunami disaster that is waiting to happen. Within a few years, in response, the prestigious Delft University of Technology, one of the leading engineering and technology educational centers in the Netherlands and the world, published a report dismantling this theory, stating that the island of La Palma is much more stable than is believed and that there will be no landslide for the next 10,000 years. “From what we know, a lot should go wrong for a disaster that seems very, very unlikely.”

What is the latest update

La Palma remains at a yellow traffic light due to volcanic risk. This warning reminds the population that they must be attentive to the news that the authorities transfer. Although, according to experts, to assure that the seismic swarm that shakes the island this week will end in eruption is “to be too early”. The head of the National Geographic Institute (IGN) in the Canary Islands, María José Blanco, recalls that this type of phenomenon occurs in all volcanic systems on the planet. “Most of them do not end in an eruption,” reassures Blanco.



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