Canada and the World
Current Events with a Canadian Perspective
Last update
02 August 2011
Mega-
Scientists say there are a small number of
geological time-
globe that may one day cause catastrophes
The Canary Islands (left), off the northwest coast of Africa, are volcanic in origin;
and therein lies a potential problem, albeit not in the immediate future.
Danger of
Volcano Splitting
La Palma is the northernmost island in the Canaries and home to the volcano Cumbre Vieja.
On August 29, 2001, CNN reported on research carried out by Dr. Simon Day of the
Benfield Greig Hazard Research Centre at University College London predicting “that
a 
future eruption of Cumbre Vieja (right) was likely to cause the western flank of
the mountain to slide into the sea.” Words such as “uncertain timing,” and “perhaps
imminent,” were bandied about.
A pile of rock “roughly the size of the Isle of Man” (The Guardian, August 10, 2004)
would be sent plunging into the ocean and would trigger a tsunami of massive proportions;
enough thought Dr. Day to send a 30-
The result would be total devastation of the coastlines of north and south America,
Europe, and West Africa.
Wave Half a Kilometre High
Geologists say undersea earthquakes such as the one that devastated coastal areas around the Indian Ocean on Boxing Day 2004 are unlikely to generate a wave height of more than about 10 metres. The truly big tsunamis are triggered by massive landslides.
One of these happened on July 9, 1958 in Lituya Bay on the northeastern shore of Alaska. An estimated 30 million cubic metres of rock was shaken loose from a mountain during an earthquake. The rock plunged 3,000 metres down the mountainside and into Gilbert Inlet.
The event has been described in an August 2008 BBC documentary “Mega-
Lituya Bay a few weeks after the tsunami. The destruction of forest along the shoreline is clearly visible.
Destruction from La Palma would be Vast
The Lituya Bay tsunami happened in an unpopulated area and, although a couple of fishing boats and their crews were lost, the only other damage was to vegetation.
A tidal wave of the type that Cumbre Vieja volcano might cause would be an entirely different story.
According to Dr. Steven Ward, of the University of California the splash of the material hitting the sea would create a dome 900 metres high. That would soon collapse but cause a tidal wave to form. The coast of Morocco would be hit, fortunately fairly sparsely populated, with a wave 110 metres high within minutes.
The eastern seaboard of the United States would take the worst hit. According to Dr. Ward’s projections, Florida would be inundated within nine hours, with a wave about 50 metres high.
As the mean elevation of the entire state is 30 metres, it’s easy to see the potential for poor outcomes. Heading for higher ground would not seem to be much of an option in the Sunshine State.
Major East Coast cities such as New York and Boston would be completely destroyed along with smaller centres such as Savannah, Charleston, Wilmington, Newport News, New Haven, and Portland. Few buildings would survive a direct hit from a wall of water 30 metres high moving at 900 kilometres per hour.
Image credits
Perrimoon
Keith Holmes
Sources
“Scientists Warn of Massive Wave.” CNN, August 29, 2001.
“Hollywood Fantasy? Tidal Wave Disaster is Just Waiting to Happen.” Ian Sample, The Guardian, August 10, 2004.
“Mega-
“World’s Biggest Tsunami.” Geology.com
“Tsunami to Hit Caribbean when Million-
© Canada and the World, August 2011
All rights reserved
JAPAN 2011
A massive undersea earthquake on March 11, 2011 triggered a tsunami that devastated the northeast coastal region of Japan.
The earthquake was one of the five most powerful to hit anywhere in the world since measurements began in 1900. Its strength was such that the island of Honshu was moved 2.4 metres to the east, and the Earth was moved between 10 and 25 centimetres off its axis.
The resulting tsunami carried waves of between four and seven metres in height that crashed ashore within 30 minutes of the earthquake. In some places the water travelled ten kilometres inland.
About 125,000 homes and buildings were destroyed or damaged and more than 20,000 lost their lives.
SOMETHING ELSE
TO WORRY ABOUT
Scientists say that at some point a large piece of the Caribbean island of Dominica will break off and collapse into the sea.
The landslide of about a million tonnes of rock will create a mega-
National Geographic News quotes geologist Richard Teeuw, from the University of Portsmouth, U.K., as saying “It is not a case of if the landslide and tsunami will happen, but when. Most likely it will be triggered by a major earthquake. It could happen in a hundred years, or it could happen next week.”