Science: Lethal shockwave from an island in the sun

Volcanic activity on the Canary Isles could send a tidal wave to devastate Florida. Phillip Henry monitors the changing shape of La Palma

It reads like the plot from a disaster movie. Florida is devastated by a tidal wave tens of metres high. The destruction and loss of life is immeasurable. The wave which caused so much devastation crossed the Atlantic in just a few hours, unseen until it reached the American coast. Its source is an unstable geological fault on the Canary Isles, more usually thought of as an idyllic holiday destination of thousands of European tourists than as the cause of disaster.

To ensure such a scenario remains in the realms of Hollywood, a group of British scientists recently travelled to the Canaries. By monitoring the fault which threatens to create the tidal wave, they hope to predict any hazard long before it could happen.

In the middle of the ocean, these waves of mass destruction - called tsunami - are almost invisible. Only when they reach the shallow waters around coasts do they become huge breakers.

The ruin caused by even a relatively small one can be apocalyptic. When the Krakatoa volcano blew itself to pieces in the last century, a tsunami six metres high killed 30,000 people.

Tsunami can also be generated when a huge landslide falls into the sea. This has never been seen in historical times but scientists have now identified the island of La Palma as a potential hazard.

"There is a danger that the side of the volcano facing west may fall into the Atlantic," says Professor Bill McGuire of the Centre of Volcanic Research in Cheltenham, who was part of the recent expedition.

"It could literally happen during the next few weeks or months or years," he said. "Equally, it could happen 100 years or more into the future. The island is very unstable and this is something which could happen fairly soon."

La Palma is not only the steepest island in the world but has also been the most volcanically active of the Canary Isles in the past 500 years. There have been two eruptions on the island this century alone - the last one was in 1971.

The volcanoes themselves do not present much danger. La Palma lava moves so slowly that most people could easily outrun it, so there is no cause for anxiety to the many tourists who visit the island. The real danger lies in the possibility that an eruption might trigger the collapse of a volcanic ridge which is unsound.

The problems started when an eruption in 1949 caused several cubic kilometres of rock to slide a few metres toward the sea. This also opened a two- kilometre-long fracture which can quite easily be seen to this day.

There are not only fears that a future eruption would cause the rock to move again, but that next time, the landslide will not stop. If this happened, the resulting tsunami would be catastrophic.

"There have been three of these collapses in the history of the island," says Juan Carlos Carracedo of the Spanish National Research Council. Not only does the landscape bear the scars of these cataclysms but submarine photos show rock from the peaks of old volcanoes far out to sea. "Another collapse is impending. The only way to prevent this hazard is to study the island closely."

By monitoring the change in shape of the mountainside, the team hope not only to discover if the western flank is slipping due to gravity but to predict if the sleeping volcano is growing restless. Before eruptions, volcanoes always swell. This swelling may be imperceptible to the human eye. Only by surveying the shape of the ground with sensitive instruments can small changes be detected.

The team of scientists used a system called electronic distance measuring (EDM). By bouncing an infra-red beam off a mirror on another ridge of the volcano and timing how long the beam takes to return, the EDM can be used to measure distances to an accuracy of a few centimetres per mile.

In late 1994, scientists set up a network of stations on the mountainside and accurately measured the distances between them. After one and a half years, they returned to measure the network again. If the distances between the stations had become greater over that period, this would suggest that either the fault had slipped or the ground was bulging as molten rock inflated the volcano.

For the moment, results show there has been no movement. While the rest of us might breathe a sigh of relief, the measurements are highly valuable to the scientists because they give them a "baseline", illustrating the behaviour of the volcano under normal conditions.

Should future studies reveal that the volcano has deviated from this, the prospect of the east coast of America being flooded by a wave from the other side of the Atlantic may turn from fiction to horrifying reality.

Suggested Topics
News
Alan Bennett has criticised the “repellent” reality shows which dominate our screens
tvBut he does like Stewart Lee
Life and Style
The Google Doodle celebrating the start of the first day of autumn, 2014.
tech
Arts and Entertainment
Sheridan Smith as Cilla Black and Ed Stoppard as her manager Brian Epstein
tvCilla Episode 2 review: Grit under the glamour in part two of biopic series starring Sheridan Smith
Sport
David Moyes and Louis van Gaal
football
PROMOTED VIDEO
News
i100
Life and Style
Vote with your wallet: the app can help shoppers feel more informed about items on sale
lifeNew app reveals political leanings of food companies
News
Former Governor of Alaska Sarah Palin, left, with her daughter, Bristol
newsShe's 'proud' of eldest daughter, who 'punched host in the face'
Sport
New Zealand fly-half Aaron Cruden pictured in The Zookeeper's Son on a late-night drinking session
rugby
Arts and Entertainment
Salmond told a Scottish television chat show in 2001that he would also sit in front of a mirror and say things like,
tvCelebrity Trekkies from Alex Salmond to Barack Obama
Life and Style
Carol O'Brien, whose son Rob suffered many years of depression
healthOne mother's story of how London charity Maytree helped her son with his depression
News
ebooksAn unforgettable anthology of contemporary reportage
Arts and Entertainment
The cover of Dark Side of the Moon
musicCan 'The Endless River' carry on the tradition? See for yourself
Life and Style
food + drink
News
Rob Merrick's Lobby Journalists were playing Ed Balls' Labour Party MPs. The match is an annual event which takes place ahead of the opening of the party conference
newsRob Merrick insistes 'Ed will be hurting much more than me'
News
A cabin crew member photographed the devastation after one flight
news
Voices
A new app has been launched that enables people to have a cuddle from a stranger
voicesMaybe the new app will make it more normal to reach out to strangers
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Pharmaceutical Computer System Validation Specialist

£300 - £350 Per Day: Clearwater People Solutions Ltd: Pharmaceutical Computer ...

High Level Teaching Assistant (HTLA)

£70 - £90 per day: Randstad Education Birmingham: Higher Level Teaching Assist...

Teaching Assistant

£50 - £80 per day: Randstad Education Birmingham: Randstad Education is the UK...

Senior Java Developer - API's / Webservices - XML, XSLT

£400 - £450 Per Day: Clearwater People Solutions Ltd: Our client is currently ...

Day In a Page

Secret politics of the weekly shop

The politics of the weekly shop

New app reveals political leanings of food companies
Beam me up, Scottie!

Beam me up, Scottie!

Celebrity Trekkies from Alex Salmond to Barack Obama
Beware Wet Paint: The ICA's latest ambitious exhibition

Beware Wet Paint

The ICA's latest ambitious exhibition
Pink Floyd have produced some of rock's greatest ever album covers

Pink Floyd have produced some of rock's greatest ever album covers

Can 'The Endless River' carry on the tradition?
Sanctuary for the suicidal

Sanctuary for the suicidal

One mother's story of how London charity Maytree helped her son with his depression
A roller-coaster tale from the 'voice of a generation'

Not That Kind of Girl:

A roller-coaster tale from 'voice of a generation' Lena Dunham
London is not bedlam or a cradle of vice. In fact it, as much as anywhere, deserves independence

London is not bedlam or a cradle of vice

In fact it, as much as anywhere, deserves independence
Vivienne Westwood 'didn’t want' relationship with Malcolm McLaren

Vivienne Westwood 'didn’t want' relationship with McLaren

Designer 'felt pressured' into going out with Sex Pistols manager
Jourdan Dunn: Model mother

Model mother

Jordan Dunn became one of the best-paid models in the world
Apple still coolest brand – despite U2 PR disaster

Apple still the coolest brand

Despite PR disaster of free U2 album
Scottish referendum: The Yes vote was the love that dared speak its name, but it was not to be

Despite the result, this is the end of the status quo

Boyd Tonkin on the fall-out from the Scottish referendum
Manolo Blahnik: The high priest of heels talks flats, Englishness, and why he loves Mary Beard

Manolo Blahnik: Flats, Englishness, and Mary Beard

The shoe designer who has been dubbed 'the patron saint of the stiletto'
The Beatles biographer reveals exclusive original manuscripts of some of the best pop songs ever written

Scrambled eggs and LSD

Behind The Beatles' lyrics - thanks to Hunter Davis's original manuscript copies
'Normcore' fashion: Blending in is the new standing out in latest catwalk non-trend

'Normcore': Blending in is the new standing out

Just when fashion was in grave danger of running out of trends, it only went and invented the non-trend. Rebecca Gonsalves investigates
Dance’s new leading ladies fight back: How female vocalists are now writing their own hits

New leading ladies of dance fight back

How female vocalists are now writing their own hits