Tsunami & Mega-Tsunami

[escargot]

[Emp edit: A thread for discussion of tsunami and megatsunami - see also the SE Asian quake/tsunami thread for the Xmas tsunami:
forteantimes.com/forum/viewtopic.php?t=19588 ]
Link is obsolete. The current link is:
https://forums.forteana.org/index.php?threads/south-east-asian-earthquake-tsunami.19588/

Megatsunami

Tidal waves which could swamp the eastern seaboard of the American continent

Scientist warns of tsunami in the making



Tidal waves which could swamp the eastern seaboard of the Americas are a more pressing concern than the chance of an asteroid causing mass destruction, according to scientists studying natural disasters.

Scientist Bill McGuire has told a news conference tens of millions of people along the eastern seaboard of the United States and Canada may drown if the slow slippage of a volcano off north Africa becomes a cataclysmic collapse.

Professor McGuire, from the Benfield Grieg Hazard Research Centre, says that some time in the next few thousand years, the western flank of the Cumbre Vieja volcano on the Canary Island of La Palma will collapse.

He says that would send walls of water 100 metres high racing across the Atlantic.

A chunk of the volcano the size of a small island began to slide into the ocean in 1949. There is almost no monitoring of the volcano, giving virtually no chance of any advance warning of an eruption which could trigger the catastrophe.

"The US Government must be aware of the threat," Professor McGuire said. "I am sure they are not taking it seriously. They certainly should be worried, as should the island states of the Caribbean."

He says the tsunami triggered by such a collapse would hit the other islands of the Spanish-owned Canaries within an hour and reach the north African coast within two hours.

Monitoring

Between seven and 10 hours later, waves still several tens of metres tall and travelling at the speed of a jet plane would swamp the Caribbean and crash into the eastern seaboards of South and North America.

Professor McGuire has urged the governments of Spain and the United States to fund monitoring of the volcanically active La Palma, a project he says would be relatively cheap.

He says the slow collapse - started by an eruption in 1949 - would almost certainly be turned catastrophic by another eruption of the volcano, which erupts every 25 to 200 years.

The last eruption was in 1971 and prior to 1949, the previous eruption was in 1712.

"A future president of the United States must make a call on what to do when La Palma collapses," Professor McGuire said.

On a brighter note, scientist Benny Peiser of John Moores University in Liverpool told the same news conference that the threat of a cataclysmic strike on the earth by a large asteroid was fading rapidly as money was pumped into finding them.

He says that within 10 to 30 years, all the near-earth asteroids will have been charted and scientists believe they can find a way to steer an asteroid out of the way of the earth, as long as they have enough warning it is coming.

 

[SoundDust]

it was on horizon a few years ago

here's a link to the programme info :eek!!!!:

Edit: Here's the text from the BBC programme page:

Scattered across the world’s oceans are a handful of rare geological time-bombs. Once unleashed they create an extraordinary phenomenon, a gigantic tidal wave, far bigger than any normal tsunami, able to cross oceans and ravage countries on the other side of the world. Only recently have scientists realised the next episode is likely to begin at the Canary Islands, off North Africa, where a wall of water will one day be created which will race across the entire Atlantic ocean at the speed of a jet airliner to devastate the east coast of the United States. America will have been struck by a mega-tsunami.

Back in 1953 two geologists travelled to a remote bay in Alaska looking for oil. They gradually realised that in the past the bay had been struck by huge waves, and wondered what could have possibly caused them. Five years later, they got their answer. In 1958 there was a landslide, in which a towering cliff collapsed into the bay, creating a wave half a kilometre high, higher than any skyscraper on Earth. The true destructive potential of landslide-generated tsunami, which scientists named "Mega-tsunami", suddenly began to be appreciated. If a modest-sized landslide in Alaska could create a wave of this size, what havoc could a really huge landslide cause?

Scientists now realise that the greatest danger comes from large volcanic islands, which are particularly prone to these massive landslides. Geologists began to look for evidence of past landslides on the sea bed, and what they saw astonished them. The sea floor around Hawaii, for instance, was covered with the remains of millions of years’ worth of ancient landslides, colossal in size.

But huge landslides and the mega-tsunami that they cause are extremely rare - the last one happened 4,000 years ago on the island of Réunion. The growing concern is that the ideal conditions for just such a landslide - and consequent mega-tsunami - now exist on the island of La Palma in the Canaries. In 1949 the southern volcano on the island erupted. During the eruption an enormous crack appeared across one side of the volcano, as the western half slipped a few metres towards the Atlantic before stopping in its tracks. Although the volcano presents no danger while it is quiescent, scientists believe the western flank will give way completely during some future eruption on the summit of the volcano. In other words, any time in the next few thousand years a huge section of southern La Palma, weighing 500 thousand million tonnes, will fall into the Atlantic ocean.

What will happen when the volcano on La Palma collapses? Scientists predict that it will generate a wave that will be almost inconceivably destructive, far bigger than anything ever witnessed in modern times. It will surge across the entire Atlantic in a matter of hours, engulfing the whole US east coast, sweeping away everything in its path up to 20km inland. Boston would be hit first, followed by New York, then all the way down the coast to Miami and the Caribbean.

 

[escargot]

Yup, ta Jima, I saw the prog then but thought something new had happened.
phew

Off to look at that hopefully reassuring link now.

 

[lopaka]

Re: Tidal waves which could swamp the eastern seaboard of the American continent

"A future president of the United States must make a call on what to do when La Palma collapses," Professor McGuire said.

Direct the Federal Emergency Management Agency to hand out surfboards?

For speculation on someone intentionally causing the collapse of the Canary Islands volcano as a terrorist weapon (!) see this reassuring thread

[Emp edit: fixing link]

 

[Anonymous]

Re: Tidal waves which could swamp the eastern seaboard of the American continent

Scientist warns of tsunami in the making



...

Professor McGuire, from the Benfield Grieg Hazard Research Centre, says that some time in the next few thousand years, the western flank of the Cumbre Vieja volcano on the Canary Island of La Palma will collapse.

Please, don't hold your breath waiting! It could be dangerous! :eek!!!!:

 

[TheQuixote]

Another article on the Mega Tsunamis:

Hollywood fantasy? Tidal wave disaster is just waiting to happen

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

Ian Sample, science correspondent
Tuesday August 10, 2004
The Guardian

It has everything you could wish for in a cliche-ridden disaster movie. A beautiful volcanic island in the Atlantic is on the brink of catastrophic collapse, threatening to unleash giant waves that will wreak havoc around the globe within hours. And while scientists try in vain to make their concerns heard, the world's governments look the other way.

But yesterday a leading expert claimed the doom-laden scenario was not only real but was being almost completely ignored by people in power.

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 metres (330ft), will be the neighbouring Canary Islands. Within a few hours the west coast of Africa will be battered with similar-sized waves.

Between nine and 12 hours after the island collapses, waves between 20 and 50 metres 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 harbours 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 metres 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.

The island came to the attention of scientists in 1949 when its volcano, Cumbre Vieja, erupted, causing a huge chunk of its western flank to drop four metres into the ocean. Scientists believe the chunk of land is still slipping slowly into the water, and say another eruption is likely to make the entire western flank collapse. "When it goes, it will likely collapse in around 90 seconds," Prof McGuire said.

Precarious

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 scientist called for an international effort to install more sophisticated sensors on the island, as well as global positioning satellite units to detect how quickly the land mass was falling into the ocean. "We need to have better monitoring so we know when an eruption is about to happen," he said. Such a system could cost as little as a few hundred thousand dollars.

"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."

Even with new monitoring equipment in place, La Palma presents a difficult problem for those charged with mitigating against natural disasters.

Little can be done to protect against the waves produced when La Palma collapses. Barriers would not be able to sustain the battering, and breaking the island apart before it collapses is either too dangerous or time-consuming.

New sensors could warn of an impending eruption two weeks in advance. But no one knows whether the island will collapse during the next eruption, or in an eruption that will not happen for centuries.

Ordering mass evacuations would have a huge financial impact that could cause resentment if it turned out to be a false alarm. The disaster could affect up to 100 million people from the coast of Africa to the Canary islands and the east coast of North America.

"The future president of the US has got to make a call at some point, that when La Palma erupts, what is he going to do?" Prof McGuire said.

"Is he going to evacuate all the major cities on the east coast? If he gets it wrong, nobody's ever going to pay attention again and he'll be out of a job."

Guardian Unlimited

 

[escargot]

This is a silly-season story which will run and run. For thousands of years.

On a R4 interview today, a scientist was asked how dangerous it was if a rock the size of the Isle of Wight fell into the sea.
'It's not the size of the Isle of Wight! It's the size of the Isle of Man!'
High comedy.

"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."

This means, 'No way am I going within a hundred miles of that island, seismometers or no seismometers.'

 

[Mighty_Emperor]

The Megatsunami: Possible Modern Threat

By Robert Roy Britt
Senior Science Writer
posted: 14 December 2004
09:49 am ET


SAN FRANCISCO -- Volcanic landslides that generate huge and devastating tsunamis tend to occur during historically warmer times on Earth, a new study suggests. Scientists don't know exactly why, but since the global climate is warming as you read this, the apparent connection was tossed out this week as a reason for scientists to be concerned about the threat now.

Tsunamis are waves that race across the ocean without much fanfare but grow to frightening proportions when they reach land. The waves are deep, and while they may appear just a few inches or feet tall on the open ocean, they can soar to the height of a multi-story building as they are forced upward near the shore.

A tsunami can be generated by the sudden uplift of the seafloor in an earthquake, or by the paddle-like effect of a landslide crashing into the sea from, say, an island volcano. Yet while quake-generated tsunamis have been observed from their genesis to the disastrous end, scientists have never witnessed a significant open-ocean tsunami generated by a landslide.

Evidence exists at various locations around the world for megatsunamis, as scientists call the largest of these events. They seem to occur every 100,000 years or so, said Gary McMurtry of the University of Hawaii.

These monsters can be hundreds of feet tall and, depending on local topography, race miles inland.

One controversial event, about 110,000 years ago, appeared to create a 1,600-foot wave in Hawaii. Yes, you read that right: Nearly one-third of a mile, or about half a kilometer.

But the evidence -- marine fossils way up there where there's no sea -- is controversial. Perhaps the islands have been rising and carried the fossils up, critics suggest.

McMurtry's team looked at marine fossils at the Kohala volcano on the main island of Hawaii, which is known to be sinking about an inch per decade. The fossils simply could not have started at a lower elevation, McMurtry said Monday at a meeting of the American Geophysical Union held here. A submarine landslide from the giant Mauna Loa volcano has been dated to the same time and, the thinking goes, caused the tsunami.

McMurtry and his colleagues also re-examined evidence for a tsunami that may have struck Bermuda and other locations in the Atlantic 420,000 years ago.

Scientists agree that submarine landslides caused by the collapse of island volcanoes -- think of the destruction of Mount St. Helens -- could generate these megatsunamis. Evidence for such landslides can be found in topography scans of seafloors around various island volcanoes, McMurtry points out.

"These giant landslides seem to occur during periods of higher than normal sea level -- like we have now," he said.

High sea levels tend to correspond with wetter climates, he said. What this has to do with landslides is not known. But perhaps, McMurtry figures, excess rainfall can serve as a trigger for the cleaving of a volcano-in-waiting.

That might all sound like a lot of logic leaps, and McMurtry is the first to admit there isn't enough data to figure out whether global warming and tsunamis are correlated. But there is some independent thinking that supports the notion.

Peter Cervelli, of the Alaska Volcano Observatory, has studied the Hawaiian volcanoes and is not involved in McMurtry's work. Cervelli said it's possible that water during extended wet periods seeps down into natural faults on the flanks of a volcano -- volcanoes are known to be more porous than other land areas -- precipitating a collapse by "bringing it closer to failure."

And in other work, Emily Brodsky of the University of California, Los Angeles has modeled the friction involved in huge volcanic landslides. She agrees that it's possible that higher rainfall amounts could make a precarious situation more slippery.

So should we worry? "Maybe," says McMurtry. He thinks that a tsunami, which can race across an entire ocean in a matter of hours, is a real threat to urbanized coastlines. Other experts agree that a large tsunami would be bad news for, say, Los Angeles or New York City. And tsunamis are not parochial. One originating in Alaska in 1964 killed people in California and generated damaging surges clear down in Chile.

McMurtry believes the threat is greater than from an asteroid impact, but asteroid research has managed to lure more funding. More money should be spent to monitor the stability of oceanic volcanoes, McMurtry argues.

"Mauna Loa is as big as it's ever been, so the energy is there" for a giant submarine landslide, McMurtry said. He's even attached some odds to the threat: "The probability of a megatsunami in Hawaii in the next 10,000 years is about 50 percent."

Source

 

[Anonymous]

More Natural Disasters

So this week you can't watch the news without seeing how a tsunami caused by an earthquake has washed away about 200,000 people near the indian ocean.

But I've seen a tv program about a potentailly worse scenario.

It's something to do with a small island which I think is off (maybe a few hundred miles off) the west coast of africa which is cracking in half and when it falls into the sea the whole west coast of america whill be hit by a much bigger tsunami than the one we have seen this week. This means hitting places like florida and new york etc..

Has anybody else heard about this?

the problem is no one can guess when it will happen, maybe next month, maybe 2000 years time, but it will happen.

 

[Anonymous]

Sorry, I meant east coast of america.

 

[SoundDust]

that'd be La Palma, there's a link to a program horizon did on it here, it has a full transcript on there too

and on here as well a few months ago

 

[Mighty_Emperor]

Chris Baker: I've merged your thread with this one (it didn't really belong in Urban Legends) - I hope this helps explain the background.

[edit: And the curious I split the SE Asian tsunami thread off to here:

www.forteantimes.com/forum/viewtopic.php?t=19588

Although a massive disaster it wasn't a megatsunami.]

 

[hallybods]

Here's a short piece on La Palma. I hope it hasn't been posted before.

http://www.rense.com/general56/waiting.htm

and more

http://members1.chello.nl/~a.horlings/nat-dis.html

 

[Yithian]

I'm not quite sure if this belongs on this here thread.

Mystery of Deadly 1946 Tsunami Deepens
By Sarah Davidson
LiveScience Staff Writer
posted: 06 December, 2004
9:00 a.m. ET

A mystery surrounding one of the most destructive tsunamis of the 20th Century just got more puzzling as a seafloor search failed to reveal the smoking gun scientists expected to find.

On April Fools Day in 1946 an earthquake off the coast of the Aleutian Islands in Alaska spawned a series of waves known as a tsunami. One wave as high as a 13-story building hit locally. Others raced across the Pacific, killing dozens and leaving a trail of destruction that stretched to California and even South America.

The earthquake was too small to spawn the huge local wave, many scientists agree, and they have struggled for decades to figure out what happened. The leading theory has been that the earthquake triggered an underwater landslide, generating a one-two punch.

But a seafloor-mapping project by Scripps Institution of Oceanography, designed specifically to look for the cause of the tsunami, didn’t find evidence to support that theory.

"We found no landslide where there should have been a landslide, where I was positive there had to be a landslide," Gerard Fryer, a geophysics professor at the University of Hawaii, told LiveScience. "I was stunned that there was nothing there."

Complex waves

Tsunamis can result from earthquakes in the seafloor, underwater landslides, and more rarely volcanic eruptions. Even an asteroid impact can trigger one.


Whatever the cause, two tsunamis are created. A local one moves toward the nearest coastline, and another travels into the deep ocean. In each case, the tsunami is actually a series of waves, much like what you can produce by paddling your hand in the bathtub.
The word tsunami is Japanese for "great harbor waves." On the open ocean, however, they are barely noticeable, looking from the surface like any other wave. But underneath, a tremendous well of energy lurks.

The height of a tsunami is not apparent until it travels up from the deep sea into the shallow waters along a coastline and rushes inland. Just as the your bathtub waves splash up the edge, tsunamis are forced upward to varying extent depending, in part, on the slope of the shore they meet.

Contrary to popular belief the surge of a tsunami does not appear as a great crashing wave. Rather, it is a very strong and fast moving tide that can destroy homes, overturn train cars, and deposit boats several block inland.

Hawaii takes the brunt

The first wave of the tsunami on that April 1st nearly six decades ago reached the big island of Hawaii in about five hours. The Hilo waterfront was destroyed. Surges as tall as two- and three-story buildings pounded several coastal villages. In Haena, the tsunami reached its maximum height -- in Hawaii, anyway -- of 45 feet (13.7 meters).

The calamity killed 159 people in Hawaii and caused $26 million in damage -- in 1946 dollars.

The Pacific Ocean is a big place, and the waves spread. Surges up to 14 feet swamped Half Moon Bay, California. One person drowned in Santa Cruz. Fishing boats were damaged as far south as Chile.

The local tsunami in Alaska rose as high as 138 feet (42 meters), according to research by Emile Okal at Northwestern University. It destroyed the steel-reinforced Scotch Cape lighthouse on Unimak Island.

It was this local surge that Fryer and Okal agree could not have been spawned by the earthquake alone.

Doesn't add up

The 1946 Alaska earthquake had a magnitude of 7.1. Based on what scientists understand about the energy and characteristics of the earthquake, it should not have been able to generate either such a large local surge or such a devastating Pacific-wide tsunami. The idea of a landslide contributing to the total energy was paired by some scientists with a theory that the earthquake was larger than the instrumentation of the day could measure.

Okal studied the earthquake and its aftershocks, which originated across a broader area than would be expected. That suggests the main temblor was more of a slow rumble than an abrupt break in the planet's crust.

The slow movement, Okal says, would have been difficult for seismometers of the era to measure. He calculates a true size of the earthquake at around magnitude 8.5, which comes close to accounting for the tsunami’s effects in Hawaii.

Yet questions surrounding the size of the local tsunami, the taller one that came ashore in Alaska, remain following the Scripps Institution's seafloor mapping expedition, which was conducted in July.

"We found seafloor evidence that will cause tsunami modelers to rethink the cause and characteristics of the 1946 tsunami," Tony Rathburn, a faculty member at Indiana State University, said in a statement last month. "Our findings make the causes of the 1946 tsunami even more mysterious."

Not giving up

Okal says it still may be possible a landslide was involved in the complex events of 1946. He said there are important variables, including where the Scripps project looked and the size of landslide the searched for.

"If they were looking for an elephant and there was only a dog, they could say there was no elephant but they weren’t even looking for the dog," Okal said in a telephone interview last week.

Fryer has some new ideas that might resolve the mystery, but he's not ready to share them. He and Okal both plan to stick with the investigation.

"Almost 60 years after the event, the 1946 tsunami is still making fools of all of us," Fryer said.

http://www.livescience.com/forcesofnature/041206_tsunami_new.html

 

[diamonddogs]

it was on horizon a few years ago

here's a link to the programme info :eek!!!!:

This was repeated last Wednesday on UK Discovery or somesuch - I watched it with a heavy heart, reflecting on the irony of TV scheduling.

 

[Anonymous]

Cumbre vieja mega tsunami

an interesting article on the possibility of a mega tsunami generqted by Cumbre Vieja collapse.

January 02, 2005

Focus: Tsunami disaster

Could an even bigger disaster strike in our lifetime?
Professor Bill McGuire, catastrophe expert, says one is already in the making. Stuart Wavell reports



Another global disaster is already in progress. Events are inexorably priming a tsunami that will kill a million people and devastate the south coast of Britain and the eastern seaboard of the United States. “It’s happening now and nothing can stop it,” says the London academic Professor Bill McGuire.
The 50-year-old scientist, who has done more than anyone to publicise the threat of giant tidal waves, hopes the Indian Ocean tragedy will shake governments out of their torpor to prepare for the next catastrophe. “Everybody wants to develop a tsunami warning system now,” he observes drily. “It would have been nice to have had one 10 years ago.”



The Boxing Day tsunami was the first global geophysical event, or “gee gee”, in living memory. It seems mild compared to the horrific scenario identified by McGuire and his team at the Benfield Hazard Research Centre at University College London.

The trigger is a volcano on La Palma in the Canary Islands. Cumbre Vieja normally erupts at intervals of 20 to 200 years and has not done so since 1971. The next eruption may dislodge an unstable 12-mile-long slab of rock the size of the Isle of Man, which will crash to the sea bed causing a dome of water a mile high. The rock is already slipping down by infinitesimal degrees. “When it goes, it will likely collapse in 90 seconds,” McGuire says.

The resulting tsunami, travelling at 500mph, would reach Britain in six hours, with waves rearing up to 33ft. “It’s the same sort of size as the waves that caused the deaths in the Indian Ocean,” McGuire notes.

Britain last received such a battering 7,000 years ago, when a huge landslide off the coast of Norway launched a 75ft wave that poured across northeast Scotland, where Aberdeen is today. “It was the biggest landslide we know of,” says McGuire.

The La Palma tsunami would reach the Americas nine to 12 hours after the dislodgement, laying waste to the eastern seaboard of the United States with waves of 165ft. Boston, New York and Miami would be destroyed and the Caribbean islands overwhelmed.

To avert disaster would require an early warning system in order to stage the largest evacuation in human history. Yet, bizarrely, La Palma has not been closely monitored since McGuire and his colleagues established four years ago that the rock slab was moving at a speed of a third of an inch a year.

The international attention generated by McGuire’s research has astonished him, and there is even a thriller based on his prediction.

Scimitar SL2, the latest book by the bestselling author Patrick Robinson, describes a terrorist plot to attack the United States by detonating La Palma’s rock slide with missile strikes.

But the US government has not acknowledged the hazard or offered funding to research it. “It’s a very blinkered outlook,” McGuire says. “I’ve had loads of e-mails from worried Americans, asking if I know when it’s going to go.” The answer is that he does not know. But the outcome remains 100% certain.

The hazards research centre was set up in 1997 at the behest of the insurance industry — its sponsor, Benfield, is the world’s third-largest reinsurance broker — to predict volcanic eruptions, tropical storms and earthquakes, as well as helping with disaster management. Its collection of vulcanologists, meteorologists and geologists comprises the largest team of its kind in Europe.

McGuire, a Scottish-Welsh volcanologist and author of A Guide to the End of the World: Everything You Never Wanted to Know, identifies another terrifying prospect waiting in the wings. Tokyo is due a repeat of the worst natural disaster in Japan’s history, in which an earthquake measuring 8.3 on the Richter scale killed 143,000 people in 1923. Tokyo and Yokohama were wracked by firestorms.

“The effect on the global economy will be devastating,” McGuire says. He estimates the cost conservatively at between £1.8 trillion and £2.3 trillion. “There will be a global crash worse than 1929.”

On the face of it, Britain is relatively safe from natural catastrophes. We are not in an earthquake zone and the last volcanic activity was in Scotland 40m years ago. But, McGuire points out: “People on the east coast of Sri Lanka felt safe for the same reasons on Christmas Day.”

Yet the British Isles are particularly vulnerable to a side effect of global warming, which McGuire rates the worst of all the “gee gees” because it is already happening and cannot be reversed for thousands of years. He believes there is a serious risk that a disruption of ocean currents, resulting from large-scale melting of Arctic ice, will “shut off” the warm water of the Gulf Stream.

“Without the Gulf Stream, temperatures in the UK and northwestern Europe would be 5C or cooler, with bitter winters as fierce as those of the so-called Little Ice Age in the 17th to 19th centuries.” The process may be already under way, he suspects.

So we will either freeze or roast. “It’s too late to stop temperatures and sea levels rising for thousands of years,” he says. “But if we don’t do anything it’s going to be much worse for our children and grandchildren. Drastic things have to be done now.” By which he means alternative energy sources, with more emphasis on wave and tidal power, and a tax on aviation fuel, one of the largest contributors to global warming.

McGuire is resigned to being called a doom-monger and makes no apology for raising another bleak spectre: a volcanic winter.

The eruption of Toba in Indonesia (not far from the epicentre of last weekend’s earthquake) 73,500 years ago threw up a pall of dust that plunged the world into a six-year winter. “Round about that time, there was a population crash that may have reduced the number of humans to a few thousand. As a race we may have been very close to extinction.”

The geological record suggests that such cataclysmic eruptions occur twice in every 100,000 years. So, bearing Toba in mind, we may be living on borrowed time. But guessing which volcano poses the greatest threat is difficult: of 3,000 active volcanos, only 150 are being monitored. Paradoxically, the greatest peril comes from volcanoes that have been dormant for a long time, McGuire says. The longer they have been quiet, the more violent the next eruption and hence the more difficult to predict.

He should know. In 1996 he was working as senior volcanist adviser on the island of Montserrat when its volcano suddenly erupted. “Magma had been oozing out of it for a year. When the first big explosive eruption took place at midnight, I thought, ‘I’ve had it’. I was about 6km away. Three of us had to go towards the volcano to check it out. If it had been a bigger event, we would have all been killed.” The eruption killed 19 people and destroyed the capital.

He fears that the next cataclysmic eruption will come from an unknown volcano in the southern Andes. “If you chose any of the well-known volcanoes you’re almost certainly going to be wrong. It’s going to be one of the 3,000 that even I haven’t heard of.”

He makes one confident prediction: the volcano of Teide in Tenerife will erupt in the second half of this year, but not disastrously.

The rest of his forecast for 2005 is bleak: a combination of climate change and more people living in coastal areas is a recipe for misfortune. “We’re going to see more deaths and disasters.”

McGuire remains optimistic, however. His next book is entitled Surviving Armageddon: Solutions for a Threatened Planet. “I don’t lose sleep,” he says. “Like everyone else, I don’t think any of these things is going to happen during my lifetime. Then you realise they do happen.”

HISTORIC KILLERS

EARTHQUAKES


240,000 Tang-shan, China, 1976
200,000 Nan-shan, China, 1927
180,000 Kansu, China, 1920
160,000 Messina, Italy, 1908
140,000 Tokyo, Japan, 1923



20TH-CENTURY TSUNAMIS


12,000 Agadir, Morocco, 1960
8,000 Papua New Guinea, 1998
5,000 Philippines, 1976
5,000 Chile, 1960
3,000 Japan/Hawaii, 1933
1,088 Japan, 1946



EPIDEMICS

21m Aids worldwide 1981-onwards
21m Influenza worldwide, 1918-20
12m Bubonic plague, India, 1896-1948
3m Typhus, eastern Europe, 1914-15

Source: http://www.timesonline.co.uk/article/0,,18690-1422952,00.html

 

[rynner2]

Doesn't seem worth starting a new thread for this. But it comes with a built-in TV reminder!

Tsunami theory of flood disaster

A tsunami in the Bristol Channel could have caused the deaths of up to 2,000 people in one of Britain's greatest natural disasters, experts have said.
For centuries, it has been thought that the great flood of January 1607 was caused by high tides and severe storms.

It is estimated that 200 square miles of land in south Wales and south west England were covered by water.

In Timewatch on BBC2 on Sunday, two experts argue a tsunami could have caused the devastation.

Eyewitness accounts of the disaster, published in six different pamphlets of the time, told of "huge and mighty hills of water" advancing at a speed "faster than a greyhound can run" and only receding 10 days later.

Professor Simon Haslett, from Bath Spa University College, said: "There is an overall theme running through the pamphlets of a destructive event, very violent, disastrous, on a scale that is unprecedented."

Australian geologist Ted Bryant, from the University of Wollongong, agreed: "The waves are described as mountainous - that's a description of a tsunami."

During the programme, Mr Haslett and Mr Bryant revealed evidence from all around the Severn Estuary backing up their theory.

This included a layer of sand in mud deposits at Cardiff's Rumney Wharf, in which pebbles and pieces of broken-up shell can be found.

They claimed that these deposits were brought in from the open ocean around 400 years ago, possibly by a tsunami.

And they argued that boulders lying on the shore in Dunraven Bay in south Wales could have been carried into their positions by the force of the onrushing waters.

"Whether it is sand on the marsh, or it's pebbles in the clay, or it's erosion on the headland or boulders piled up in key spots, you go for the simplest explanation, and I can put down most of the signatures we have seen by one wave," said Mr Bryant.

However, Dr Devin Horsburgh, from the Proudman Oceanographic Laboratory in Liverpool, said some of the phenomena found could have been caused by a massive storm surge, formed by a combination of high tides and hurricane winds.

"A storm surge is going to provide some billions tonnes of water rushing across the flood plain and is more than capable of picking up enormous rocks and large amounts of sediment and depositing them a long way away," he said.

Further evidence supporting the tsunami theory came from Dr Roger Musson, head of seismic hazards at the British Geological Survey, who said there were other examples of earthquakes in the area caused by an ancient fault off south-west Ireland.

One quake, measuring 4.5 on the Richter scale, was recorded there on 8 February 1980.

"The idea of putting a large historical earthquake in this spot is not so fanciful," he said.

"We know from seismological evidence, that we have actually had an earthquake here - so there is a fault and it is moving, it is active."

Other UK tsunamis include a 70ft high wave that hit Scotland 7,000 years ago, following a massive landslip in Norway.

Three months ago, a tsunami triggered by a submarine earthquake near northern Indonesia killed nearly 300,000 people.

The Killer Wave of 1607, a Timewatch special, is repeated at 1910 BST on BBC2 on Sunday 3 April.

 

[ramonmercado]

Cost of 1607 flood repeat '£13bn'

The shaded area of the map was hit by the 1607 disaster
A repeat of a storm surge that caused severe flooding in south Wales and south west England 400 years ago would be the UK's costliest natural disaster, claims a new report.
A risk management company has calculated that a similar event in the Bristol Channel could cost £13bn.

Experts on freak weather and tsunamis hold a forum in Newport on Saturday.

High tides and storms or a tsunami are theories for causing the deaths of up to 2,000 people on 30 January 1607.

It is estimated 200 square miles (520 sq km) of land in south Wales and south west England were covered by water.

1607 FLOOD FACTS

The flood reached a speed of 30mph and a height of 25ft
It swept up to four miles inland in north Devon, Pembrokeshire, Glamorgan, Monmouthshire, Cardiff and Somerset.
In low-lying Somerset levels, it reached 14 miles inland
In 2002, experts from Bath and Australia, proposed the tsunami explanation over the idea that the flood was caused by a freak high tide

Dr Claire Souch, director of model management at Risk Management Solutions (RMS) and a co-author of the report claims that an "exceptional event" on the scale of the 1607 flood, with a storm surge of nine metres, could overwhelm existing flood defences.

More than 80% of the total losses from the same event today would occur in the cities of Bristol, Cardiff and Gloucester, with the remaining losses along the south-western coast of Wales and around Barnstaple in Devon.

Dr Souch said: "We've run a variety of simulations of a storm surge coming up the Bristol Channel today and in the worst case scenario the flood heights would be so high, they would over-top existing defences and cause flooding over an extremely large area.

'Wall of water'

"This could lead to damage totalling as much as £13bn. which would indeed make it the costliest disaster in the UK."

Dr Souch said it had to be made "very clear" that the chance of a repeat was small, with a probability of it being an event which could take place on average every 500 to 1,000 years.

"It's not something we can expect over the next few years but it could happen - and it last happened 400 years ago".


Timewatch used computer graphics to recreate what the wave could have looked like

One theory was that a tsunami caused the flood, based on accounts from the time and also geological research of mud deposits and boulders found in south Wales.

But Dr Souch believes it was caused by an exceptional set of circumstances.

"That theory has been around for a while, but there's been a lot of other scientific research which has now effectively disproved that theory.

"The work done by the Proudman Oceanographic Laboratory [in Liverpool] has shown it was really a combination of a very high spring tide and almost at exactly the same time a storm system coming in off the Atlantic, driving the waves ahead of it and pushing up this wall of water, which can be funnelled up the estuary."

Eyewitness accounts of the 1607 disaster told of "huge and mighty hills of water" and only receding 10 days later.

The extreme tidal forces of 30 January are estimated to occur about every 4.5 years and are next expected on 20 March 2007.

The forum is being held at the University of Newport, Caerleon.



http://news.bbc.co.uk/2/hi/uk_news/wales/6305013.stm

 

[ramonmercado]

Ooo arhh!

May 3rd 2007
From The Economist print edition


A tsunami may have struck Britain 400 years ago



IN 1607 a sudden flood around the Bristol Channel in south-west Britain killed at least 2,000 people. It was the worst natural disaster ever recorded in a country which, last week, devoted headlines to an earthquake that knocked over a few chimney pots. But on that sunny January 30th four centuries ago, a fully laden 60 tonne ship in Appledore harbour, north Devon, was picked up and dumped in nearby marshland. The waters took one Mistress Van before she could reach the higher rooms of her house. She was caught unawares because she lived more than four miles (around 6km) from the sea.

That this huge flood happened is undisputed. It is commemorated in church plaques in the coastal counties of Somerset and Monmouthshire. But why it happened is another matter. For the past five years Edward Bryant and Simon Haslett of the University of Wollongong in New South Wales, Australia, have propounded the idea that a storm surge may have been wrongly accused. They think the flood was caused by a large tsunami that began off Ireland. They outline their evidence in this month's Journal of Geology.

The Bristol Channel is shaped like a funnel. That means it experiences smaller storm waves in its inner regions, which are narrow and shallow, than in its wider, deeper parts. Conversely, a tsunami wave rolling up the channel would grow in height as it became increasingly constricted. Dr Bryant and Dr Haslett looked at large boulders that had been transported onto the land by the sea in this region. Had a storm surge moved these boulders, Dr Bryant and Dr Haslett calculate that its waves would have to have been seven times higher than those of the largest storm waves ever recorded in these parts. A tsunami is more plausible.

Next they looked at the arrangement of the boulders. Rather than being dribbled erratically over the land, many form overlapping “trains” like roof tiles, oriented along the direction from which a tsunami would have struck. This pattern is more pronounced as the channel becomes narrower and turns into the Severn estuary.

Finally Dr Bryant and Dr Haslett found four examples of coastal bedrock that has recently been sculpted by high-energy vortices. That is an after-effect associated with historical tsunamis.

What might have caused such a tsunami is unclear. One possibility is a submarine landslide. Another is an earthquake at sea. Such earthquakes are rare in the geologically placid British Isles. But, as the people of Kent have just discovered, they do occasionally happen.


http://www.economist.com/science/Printe ... id=9111439

 

[ramonmercado]

News of an even older Tsunami.

Ancient Tsunami Carried Giant Boulders to Tonga
http://news.nationalgeographic.com/news ... 14366.html
Rebecca Carroll
for National Geographic News

September 30, 2008

Huge coral boulders on Tonga's main island of Tongatapu were possibly tossed hundreds of feet inland by one of the largest tsunamis ever triggered by a volcano.

Researchers believe the ancient wave may have hit the island's shore sometime within the past 7,000 years, after the melting of the most recent ice age brought sea levels to roughly where they are today.

The largest of the seven boulders is 50 feet (15 meters) wide and estimated to weigh 1,600 tons. It currently sits more than 300 feet (100 meters) from the sea and 30 feet (10 meters) above sea level, an anomaly on the South Pacific island's flat landscape.

"We suspect that this may be the largest [object] moved uphill by a tsunami," said Cliff Frohlich, a senior scientist at the Institute for Geophysics at the University of Texas at Austin.

"It wasn't like we found these rocks everywhere in Tonga," Frohlich noted. "We found them just in one place on one island."

By comparison, the 130-foot (40-meter) waves triggered by the 1883 eruption of the Indonesian volcano Krakatau—the most powerful explosion in recorded history—are known to have moved a boulder only about a third that size the same distance, Frohlich said.

It's possible there simply were no larger boulders for that tsunami to displace, he added. But he and his colleagues believe the Tonga tsunami may have been as big or larger than Krakatau's.

The team will be presenting some of its findings at a geology conference in Houston on October 5. Their study is currently under peer review.

Striking Distance

The sea was likely close to present-day levels when it carried the boulders, which Frohlich believes were formed in the reefs surrounding the island.

The coral boulders were alive and growing about 122,000 to 130,000 years ago. It's possible that this is when the wave occurred, but the researchers favor a more recent date.

They estimate it struck within the last 7,000 years, because the surrounding area lacks the erosion and other signs of weathering one would expect after more than 100,000 years.

Volcanic Disaster

Tsunamis are usually caused by earthquakes, underwater landslides, or volcanoes. They can also be triggered by meteor strikes, but there was no evidence that a meteor landed near Tonga, Frohlich said.

Initially, earthquakes were the most obvious candidate. But the wave struck Tongatapu's western shore, and an earthquake-triggered tsunami would have come from the east, where the fault line lies.

(Related: Explore a map of Earth's tectonic plates.)

"It just didn't smell like an earthquake," Frohlich said.

The scientists used computer models to determine the power that nearby underwater landslides could have had, but "we couldn't get waves high enough," he said.

The researchers believe the wave was most likely triggered by one in a string of underwater volcanoes about 21 miles (35 kilometers) away from the island.

A 2007 mapping survey of the seafloor near Tonga revealed flank collapses and calderas, geological features generated by volcanic instability or extraordinarily large eruptions.

Eyes Opened to Tsunamis

Team member Allan Morton, a retired geology professor from Central Arizona College, first identified the massive boulders in a 2003 paper on evidence of tsunamis in Tonga.

"There's a general feeling in Tonga they don't have tsunamis," Morton said, noting that the most recent recorded event was in 1919.

The study could help raise awareness of the dangerous waves in Tonga, helping its people to be better prepared, he said.

(See aerial views of tsunamis)

Dale Dominey-Howes, director of the Australian Tsunami Research Center, was not involved in the research.

"What they have found is interesting and, if proved, is profound in terms of improving our understanding of potential volcano-triggered tsunami in the Southwest Pacific," he said.

The finding could also have implications for Australia's eastern seaboard. An extension of the Tonga volcano line runs north-south about 1,600 miles (2,500 kilometers) east of Australia.

"Work is underway to try and evaluate which marine-based volcanoes in the Southwest Pacific might have the capacity to generate eruption tsunami," Dominey-Howes said in an e-mail. "We'll have a better idea in a year or two."

 

[rynner2]

Tsunami Stones

The mystic stone at tsunami tide's highest point that saved tiny Japanese village from the deadly wave
By Daily Mail Reporter
Last updated at 11:46 PM on 21st April 2011

This four-foot high stone may look unremarkable, but it is credited with saving the lives of the population of Aneyoshi when the tsunami struck Japan.
Carved into its weather-worn rock is a warning - 'Do not build your homes below this point!' - because they would be at risk from floods in a tsunami.
The villagers obeyed the ancient warning and the tiny community of just 11 houses and 34 residents were rewarded with survival at a key geographical point.

Aneyoshi, in the mountains of stricken Iwate Prefecture, bears a significant mark of the national natural disaster.
Just 300ft down the hill from where the stone sits is a blue line painted on the road. It marks the point in Japan where the tsunami water reached its hightest point - 127.6 feet.
The previous record height reached by flood waters in Japan was 125.3ft, which was also reached in Iwate Prefecture during a tsunami in 1896.

It is Japan's history of tsunami's that led to these warning stones becoming a familiar sight along the coast of Japan as ancestors tried to warn future generations of the dangers. Some of the stones are 600 years old.
'The tsunami stones are warnings across generations, telling descendants to avoid the same suffering of their ancestors,' Itoko Kitahara, a specialist in natural disasters at Ritsumeikan University in Kyoto, told the New York Times.

It was a tsunami in 1896 which killed 22,000 people that first convinced the people of Aneyoshi to move to their hilltop retreat and remain there.
After a period of stability the population renewed itself and slowly began moving back down the hill towards the coast, but a then in 1933 another tsunami struck and left four survivors.

It was after that disaster that the stone was erected and the village credits that with saving the village from a tsunami in 1960.
'They knew the horrors of tsunamis, so they erected that stone to warn us,' said Tamishige Kimura, 64, Aneyoshi's leader.

However, the magnitude 9.0 earthquake on March 11 which killed 29,000 people was the most destructive to strike Japan since the Jogan earthquake in 869.
Although the village was unharmed, it still lost a family of four. Mihoko Aneishi, 36, and her three children were swept away in their car while in a neighbouring town.

The Aneyoshi stone informs 'high dwellings ensure the peace and happiness of our descendants' but a scared history of disasters is clear in many of the place names. Nokoriya translates as Valley of Survivors while Namiwake means or Wave’s Edge.

Many villages ignored the warnings on the stones, considering them relics of a bygone age, and built their houses closer to the coast. It proved a fatal mistake for so many.
'As time passes, people inevitably forget, until another tsunami comes that kills 10,000 more people,' said author and tsunami expert Fumio Yamashita.
No-one can forget the last disaster though and its effects continue to be felt.

...

Read more: http://www.dailymail.co.uk/news/article ... z1KF7SbywR

 

[ramonmercado]

Not quite a mega tsunami. Vid at link.

Underwater landslide likely cause of 'mild tsunami'
http://www.bbc.co.uk/news/uk-england-devon-13955321

Sailor Bob Brown said the tidal surge swept down the Yealm estuary near Plymouth, at "about four times the normal speed"

A "mild tsunami" along the South West coast was probably caused by an underwater landslide, a coastal expert has said.

The unusual tidal surge struck the Cornwall, Devon, Dorset and Hampshire coastline on Monday morning.

There were reports of rivers changing direction, fish leaping out of water and hair standing on end due to static.

Dr Mark Davidson, from the University of Plymouth, said the surge was quite a "rare" occurrence.

The first reports of the event came from St Michael's Mount in Cornwall.

Boatman Dave Ladner said: "The funniest thing was on the causeway all the ladies' hair was standing on end with the static.
Continue reading the main story
“Start Quote

...it was pouring over the causeway like a torrent”

End Quote Roland Stewart

"The sea on the eastern side was probably 8ins (20cm) to a 1ft (0.3m) higher than the rest and it was pouring over the causeway like a torrent rather than just a gentle meeting in the middle."

Roland Stewart from Millbrook, near Plymouth, said: "It was quite violent in a way, my dinghy was moving around with the movement of the water and I just wondered what the hell was going on.... within 15 minutes it was all over."

Amateur video footage shot on the Yealm estuary, to the east of Plymouth, shows the surge.

Bob Brown was launching his dinghy at the mouth of estuary at 1015 BST, an hour after low tide when he saw the wave.

He said: "The tide was coming in from left to right, all of a sudden it stopped coming in from the sea and went back the other way.

"It came back at quite a force, all the boats were bobbing around.
Causeway at St Michael's Mount The sea at St Michael's Mount is normally "a gentle meeting in the middle" of the causeway

"To see a tide suddenly stop and go back the other way at four times the speed was unbelievable."

He said a local landowner told him the first thing he noticed was "lots and lots of fish jumping out of the water".

Dr Davidson, an associate professor in coastal processes, told BBC Spotlight: "[Surges] are quite rare and it's probably not a tidal phenomenon.

"It's probably more likely to be a tsunami of some kind, obviously it's quite mild.

"It's probably not due to an earthquake, which is the normal source.

"It's probably more likely to be a sub-marine landslide."

According to the Tidal Gauge Anomaly measure, which records the difference between the forecast tide and the actual tide, the anomaly on Monday morning in Newlyn, Cornwall was 0.2m (0.7ft), in Plymouth 0.3m (1ft) and in Portsmouth 0.4m (1.3ft).

The MET Office in Exeter said it did not think anything in the weather could have caused the change in the tidal pattern.

The British Geological Survey said there was no seismic activity in UK waters over the weekend.

 

[markrkingston1]

Not quite a mega tsunami. Vid at link.

Underwater landslide likely cause of 'mild tsunami'
http://www.bbc.co.uk/news/uk-england-devon-13955321

I am quite surprised this did not result in more discussion or speculation. Despite its small size it is nevertheless a very unusual event and the 'static electiricty' angle is most intriguing,



**edit**
Fixed typos.

 

[Number 6]

Not quite a mega tsunami. Vid at link.

Underwater landslide likely cause of 'mild tsunami'
http://www.bbc.co.uk/news/uk-england-devon-13955321

I am quite surprised this did not result in more discussion or speculation. Despite its small size it is nevertheless a very unusual event and the 'static electiricty angle is most introguing,

Couldn't agree more - why is nobody seemingly interested that there was a lot of static electricity? What caused it?

 

[rynner2]

It was an interesting event, especially to me as I know the places mentioned. I don't know what caused the static electricity, but that was only reported at St Michaels Mount, unless the jumping fish in the Yealm were also feeling it. (But for the fish it may have just been fear of being stranded in the shallows.)

Such water movements as shown in the video are not that uncommon, in fact. In Salcombe, south Devon, something similar happens near high water, with miniature tidal bores running up the creeks. Locals say "There's a Run on." The Run occurs when there are heavy swells running in the English Channel, and the bigger ones push water over the bar, creating a small but sudden rise in height of the estuary, which is then amplified in the shallow creeks. I expect this event last June in the Channel also caused a Run in Salcombe, but it would have had less impact there, as most people would have seen it before. 8)

 

[ramonmercado]

Persian invaders of Greece 'did perish in tsunami'
http://www.bbc.co.uk/news/world-europe-17783788

Related Stories

Animated guide: Tsunamis

German geologists believe a tsunami recorded by the ancient historian Herodotus did indeed protect a Greek village from Persian invaders.

They say they have found evidence in northern Greece that the event in 479 BC saved the village of Potidaea.

Herodotus recorded that huge waves had killed hundreds of Persian soldiers during the siege of the village.

The scientists from Aachen University warn the area may experience another massive marine event.

They say that northern coastal regions should be included among the Greek regions prone to tsunamis.

Continue reading the main story
“
Start Quote

Then there came upon them a great flood-tide of the sea, higher than ever before, as the natives of the place say, though high tides come often ”

Herodotus
Translation by G C Macaulay
The History of Herodotus
It is usually the southern coast of Greece which is identified as a risk area.

Greek geophysicists say earthquakes pose a much greater threat to the country than tsunamis.

"We have found several historic tsunamis on the coast," Aachen's Professor Klaus Reicherter told Germany's DPA news agency.

"That means there is a certain risk for the coastal areas."

Sediment on the northern Greek peninsula where Potidaea and the modern town of Nea Poteidaia are located shows signs of massive marine events, such as large waves, the Aachen study found.

Excavations in the suburbs of the nearby ancient city of Mende uncovered sea shells likely to have been lifted from the ocean bed and tossed about during a tsunami.

The findings were presented at the annual conference of the Seismological Society of America in San Diego, California.

Herodotus records: "Then there came upon them [the Persians] a great flood-tide of the sea, higher than ever before, as the natives of the place say, though high tides come often.

"So those of them who could not swim perished, and those who could were slain by the men of Potidaia who put out to them in boats."

 

[rynner2]

Japan's tsunami dock washed up in US state of Oregon

A huge dock torn from a Japanese port by last year's tsunami has washed up in the US state of Oregon - 8,050km (5,000 miles) across the Pacific.
The 20m-long (66ft) concrete dock weighing 165 tonnes was spotted on Agate beach, south-west of Portland.
A Japanese consulate official said a commemorative plaque showed it had come from the fishing port of Misawa.

Radiation checks proved negative, but scientists say invasive species foreign to the area may have hitched a ride.
A starfish native to Japan was among the marine life still clinging to the structure, Oregon Department of Parks and Recreation spokesman Chris Havel was quoted as saying by the Associated Press news agency.
"This is tsunami debris, not just from Japan, but from the tsunami itself," Mr Havel said.
Oregon police have now been deployed to keep people from climbing on the dock, which was first mistaken by local residents for a barge.

Misawa lost four docks during an earthquake and resulting tsunami on 11 March 2011. Two docks are still missing.

This April, the US Coast Guard used cannon to sink a crewless Japanese ship that drifted to Alaska after the tsunami.

A month later, a Japanese owner of a Harley-Davidson motorbike swept away by the tsunami was amazed to find out that it had been washed up inside a container on a beach in Canada - about 6,400km away.

Japanese scientists estimate that some 20 million tonnes of debris were generated by the earthquake and the incoming rush of water.
Most would have stayed on land, and a fair proportion pulled out to sea would have sunk rapidly. But it is possible a million tonnes of debris is still afloat.

Nearly 16,000 people were killed by the quake and tsunami in Japan.

http://www.bbc.co.uk/news/world-us-canada-18349741

 

[ramonmercado]

Possible historical tsunamis along the South-West coast of Ireland.

Tsunamis may have hit Kerry coast
http://www.irishtimes.com/newspaper/ire ... 10205.html
ANNE LUCEY

Tue, Jul 24, 2012

THE POSSIBILITY that the south Kerry coast has over the centuries been struck by long tsunami waves of over 50ft in events that have lived on in folk memory has been raised by an archaeologist.

Cross-checking folk tales with archaeological and geological evidence, Alan R Hayden, director of more than 200 medieval excavations since 1987 in Ireland, said the grouping of Valentia, Beginish and Church islands may bear the scars of earthquakes and tsunami-type waves in medieval times.

His research is reported in the current edition of the Journal of the Kerry Archaeological and Historical Society.

Damage to the south and southwest surrounding walls of Church Island, an important early medieval ecclesiastical site, was unlikely to have been caused by a storm or heavy swell, he concluded.

Instead, the disappearance of the dry-stone wall at the south of Church Island could be due to the much longer wavelength of a tsunami, probably coming from an earthquake in the southwest.

There are indications that Church Island may have been connected to Beginish Island but that the wave led to erosion of the connecting land. A sand bar still partly connects the two islands.

The island became home to a monastic settlement in the seventh century but before that it was a centre for fuel for iron smelting.

A folk tale collected by a teacher in the early part of the last century offers an explanation for local place names connected to a road that ran from Dolus Head through the islands to Skellig.

The road, a pre-medieval structure, is called Bóthar na Scairte, or road of the cataclysm, and it is traceable for some distance on Valentia. In the folk tale the road and a local hero were destroyed by a great cataclysm, probably an earthquake followed by a wave.

According to the tale, “a terrible wave 50ft high” rushed towards a gathering of people on a summer day on Valentia. Everyone except the hero scrambled to higher ground. The wave separated Skellig and Valentia from each other.

According to Mr Hayden, the occurrence of tsunamis affecting the south and west coasts of Ireland is surprisingly well documented. The 1775 Lisbon earthquake caused a tsunami which reached Kinsale and which flooded the Spanish Arch in Galway, for example.

In the 1850s a tidal wave washed 15 men off the cliffs of Inishmore, he noted.

“The British Geological Survey has suggested that earthquakes on a known unstable fault that lies off the southwest coast of Ireland may have caused some of these tsunamis,” Mr Hayden wrote.

 

[markrkingston1]

Possible historical tsunamis along the South-West coast of Ireland.

Tsunamis may have hit Kerry coast
http://www.irishtimes.com/newspaper/ire ... 10205.html
ANNE LUCEY

I can't help feeling that the possibly greater-than-generally-expected prevalence of tsunamis in this area might be relevant to analysis of the 1607 Bristol Chanel Flood.

 

[ramonmercado]

Possible historical tsunamis along the South-West coast of Ireland.

Tsunamis may have hit Kerry coast
http://www.irishtimes.com/newspaper/ire ... 10205.html
ANNE LUCEY

I can't help feeling that the possibly greater-than-generally-expected prevalence of tsunamis in this area might be relevant to analysis of the 1607 Bristol Chanel Flood.

Indeed. I'll keep an eye out for further research regarding this.