Canary island La Palma experiences 40 tremors in 48 hours as scientists keep a close eye on its active volcano

Canary island La Palma experiences 40 tremors in 48 hours as scientists keep a close eye on its active volcano

The Canary holiday island of La Palma has recorded dozens of mini-earthquakes over the weekend, scientists report.

La Palma has a potential for a mega-landslide there. This volcanic flank collapse would be immense – the proposed volume is up to about 500 cubic kilometers. The idea that gained some popular traction is that this landslide could generate a tsunami that would devastate a large part of the coastline on both sides of the Atlantic.

The idea of such an event developing is the events of the major eruption in 1949. During this event, a fault structure was observed to develop along a part of the Cumbre Vieja ridge. This has been interpreted as indicating movement of the flank of the volcano towards the west, and thus the development of a potential flank collapse landslide on the southern part of La Palma.

Canary island La Palma experiences 40 tremors in 48 hours as scientists keep a close eye on its active volcano
The trace of the fault scarp of Cumbre Vieja, merging into one of the volcanic craters.

La Palma, like the other islands of the Canary Island archipelago, is a volcanic ocean island. The volcano rises almost 7 km (4 mi) above the floor of the Atlantic Ocean

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Canary island La Palma experiences 40 tremors in 48 hours as scientists keep a close eye on its active volcano

La Palma was rocked by more than 40 seismic movements of low magnitude and intensity between 1.5 and 2.7 on the Richter scale, according to the data of the National Geographic Institute.

The biggest earthquake, recorded at around 1pm on Saturday, had a magnitude of 2.7 and took place in the area of the Natural Park Cumbre Vieja, 28 kilometres deep.

The second largest quake, of 2.6, took place at 1.23pm on Sunday in the same area, while the third quake erupted at midnight on Monday, reaching a magnitude of 2.1, according to the Volcanological Institute of the Canary Islands (Involcan).

In the following hours, another ten tremors were recorded, taking the total of mini-earthquakes until Tuesday to 50, according to the National Geographic Institute (IGN).

María José Blanco, director of the National Geographic Institute in the Canary Islands, said the island has “never recorded a similar swarm” and although the energy levels are low and very deep, it is different from the seismic activity they have recorded so far.

Canary island La Palma experiences 40 tremors in 48 hours as scientists keep a close eye on its active volcano

La Palma is the most north-westerly island of the Canary Islands, and is home to some 86,000 people – a population which increases significantly during tourist season.

Like the other Canary Islands, La Palma is volcanic and is considered the most ‘active’ in the archipelago.

The last significant seismic activity in the archipelago took place in 2011 on the island of El Hierro, which finally led to the eruption of an underwater volcano in the southeast of the island.

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Canary island La Palma experiences 40 tremors in 48 hours as scientists keep a close eye on its active volcano

The most recent eruption on the island, which saw the Cumbre Vieja – ‘Old Summit’ – volcano erupt, took place in 1971.

The current event has been dubbed a ‘seismic swarm’, and while unusual, large numbers of these smaller tremors are not abnormal, the director of the IGN in the Canary Islands, María José Blanco, told Canarias7.

However, she added that they had “never recorded a similar swarm’ since monitoring began on La Palma.

The IGN and the Volcanological Institute of the Canary Islands (Involcan) have increased surveillance on the island to monitor the increase in seismic activity.

A spokesperson for Involcan told Canarias7 that ‘seismic swarms’ are ‘absolutely normal’ for an active volcano. such as Cumbre Vieja.

Canary island La Palma experiences 40 tremors in 48 hours as scientists keep a close eye on its active volcano

Scientist says governments are ignoring threat of a piece of rock as big as the Isle of Man crashing into the Atlantic

Bill McGuire, the director of the Benfield Grieg Hazard Research Centre at University College London, said a huge chunk of rock, roughly the size of the Isle of Man, was on the brink of breaking off the volcanic island of La Palma in the Canaries.

When – Professor McGuire says it is not a matter of if – the rock plunges into the ocean it will trigger giant waves called mega-tsunamis.

Travelling at speeds of up to 560mph, the huge walls of water will tear across the ocean and hit islands and continents, leaving a trail of destruction.

Mega-tsunami waves are much longer than the ones we are used to.

“When one of these comes in, it keeps on coming for 10 to 15 minutes,” Prof McGuire said.

“It’s like a huge wall of water that just keeps coming.”

Computer models of the island’s collapse show the first regions to be hit, with waves topping 100 meters (330ft), will be the neighboring Canary Islands. Within a few hours the west coast of Africa will be battered with similar-sized waves.

Canary island La Palma experiences 40 tremors in 48 hours as scientists keep a close eye on its active volcano

Between nine and 12 hours after the island collapses, waves between 20 and 50 meters high will have crossed 4,000 miles of ocean to crash into the Caribbean islands and the eastern seaboard of the US and Canada.

The worst-hit will be harbors and estuaries, which will channel the waves inland. The loss of life and destruction to property will probably be immense, according to Prof McGuire.

Britain would not escape entirely, he added. Waves of around 10 meters are likely to strike the south coast four to five hours after the island collapses, causing damage to seaside resorts and ports.

Such devastating natural disasters are rare, occurring on average every 10,000 years. But La Palma could collapse much sooner than that. “The thing about La Palma is we know it’s on the move now,” Prof McGuire said.

“When it goes, it will likely collapse in around 90 seconds,” Prof McGuire said.

Canary island La Palma experiences 40 tremors in 48 hours as scientists keep a close eye on its active volcano

Despite the potential scale of the threat, little is being done to monitor the geological activity of La Palma. Only a few seismometers have been set up on the precarious western flank of the island, which do not provide enough information to predict when another eruption might occur.

“It’s really a worrying situation,” Prof McGuire said. “It will almost certainly go during an eruption. The problem is that with just a few seismometers on the island, we may not get the notice we need.”

“The US government must be aware of the La Palma threat. They should certainly be worried, and so should the island states in the Caribbean that will really bear the brunt of a collapse.

“They’re not taking it seriously. Governments change every four to five years and generally they’re not interested in these things.”




 
Mary Greeley News
www.marygreeley.com

Credit http://www.dailymail.co.uk/news/article-4966466/Volcanic-island-La-Palma-experience-40-tremors-48-hours.html
https://www.theguardian.com/uk/2004/aug/10/science.spain

http://blogs.agu.org/landslideblog/page/5/