The eruption of Cumbre Vieja, on the island of La Palma, in the Canary Islands, has brought attention back to a theory from 17 years ago that concerned this very volcano.

In 2004, Professor Bill McGuire called a press conference talking about the threat of a 50-meter-high wave that would sweep away New York and the entire East Coast , news that immediately alerted Americans, burned three years earlier by the drama. of the Twin Towers and accustomed to a series of catastrophic films.

That theory, upon closer examination, proved unreliable. In short: a tsunami, even of enormous size, originating from the collapse of the walls of the Cumbre Vieja volcano in the Canary Islands would not threaten the Atlantic coasts of the United States.

McGuire

According to McGuire, an eruption of Cumbre Vieja on the island of La Palma could cause the detachment of over 1,000 square kilometers of surface which, falling into the Atlantic Ocean, could give rise to a gigantic wave that in 6-8 hours would reach the American coasts.

Scientists know that collapses of volcanic buildings caused disastrous tsunamis also in the Mediterranean ( Santorini around 1600 , BC Etna 8,000 years ago , in Anak Krakatoa in Indonesia 2018 between Sumatra and Java ) and represent a serious danger.

McGuire, then director of the Benfield Grieg Hazard Center at University College London, accused the governments of the countries concerned of not taking the threat seriously enough.

Unheard

But McGuire was, in part, an unheard prophet. Four months later, on December 26, 2004, a 9.2 magnitude earthquake in Indonesia caused a tsunami that swept the shores of the Indian Ocean causing about 250,000 deaths. The world was completely unprepared for such an event, and it was only after that that coastal prevention programs and early warning systems such as ocean buoys were put in place.

High risk

Cumbre Vieja is a volcano with a high risk of collapse. More recent studies, however, have noted that the previous collapses of the volcano took place in prolonged times, so it is very unlikely that there will be a general collapse like the one feared by McGuire, perhaps possible every 40-90 thousand years (the last in the Canary Islands of the El Hierro volcano occurred 15 thousand years ago).

Prolonged and partial collapses, with a low slip angle and limited speed of entry into the water, would therefore not be able to cause mega oceanic tsunamis.

However, it represented - yes - a serious danger for the coasts of La Palma and the other Canary Islands. As happened on December 30, 2002 in Stromboli for the landslide in the sea of ​​a portion of the Sciarra del fuoco .