After seeing the devastation in Japan recently, I was wondering how vulnerable we are here on the East Coast to Tsunamis.
I found an interesting article with some important historical data. Pretty crazy stuff! Scientists say that it's a question of "WHEN", not "IF"!
For those who prefer not to read:
Nutshell version:
There is a volcano off the coast of Africa. WHEN it erupts, it will cause a Tsunami 75 feet high traveling at a velocity of 700 MPH (as fast as a jet) that will hit the Eastern Seaboard.
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An East Coast, Underwater-Landslide Source of Giant Waves
There are increasing signs that the outer sloping edge of the continental shelf along the East Coast has the potential to cave in, possibly abruptly enough to send destructive "tidal waves", or tsunamis, speeding toward shore. The latest evidence comes in a study published in Science (July 14, 2000) which found that sediment buried nearly 2,000 feet under the seabed off New Jersey is so porous that it is actually mostly water.
As stated in the New York Times (7/14/2000):
Just as stepping on a water-filled balloon can cause its sides to bulge and burst, so too could the weight of rock over the soggy sediments cause the water to blow out the side of the continental slope, potentially causing an underwater landslide and subsequent giant waves, the authors say.
The report says the area studied, about 100 miles east of Atlantic City, is particularly waterlogged, and thus particularly unstable, because the deep layers of the shelf were formed in the last Ice Age, when the Hudson River was a turbid torrent, laying down enormous amounts of silt that trapped water as successive layers accumulated.
"It's a system that's in a critical state because of those fluid pressures," said Dr. Peter B. Flemings, a geologist at Pennsylvania State University who wrote the paper with Brandon E. Dugan, a doctoral candidate at the university. What is not yet known, Dr. Flemings said, is if this condition will result in a succession of small crumbling failures or in occasional canyon-carving, wave-spawning collapses."
Giant Waves Originating Off Northwest Africa
Now here, courtesy of the BBC, is information that captures another giant-wave-generating source, this time from a collapsing volcano.
GIANT WAVE COULD THREATEN US
The wave would sweep up to 20 km inland. A collapsing volcano in the Atlantic could unleash a giant wave of water that would swamp the Caribbean and much of the eastern seaboard of the United States, a scientist has claimed.
Dr Simon Day, of the Benfield Greig Hazard Research Centre at University College London, UK, believes one flank of the Cumbre Vieja volcano on the island of La Palma, in the Canaries archipelago, is unstable and could plunge into the ocean.
Swiss researchers who have modelled the landslide say half a trillion tonnes of rock falling into the water all at once would create a wave 650 metres high (2,130 feet) that would spread out and travel across the Atlantic at high speed.
The wall of water would weaken as it crossed the ocean, but would still be 40-50 metres (130-160 feet) high by the time it hit land. The surge would create havoc in North America as much as 20 kilometre (12 miles) inland.
Dr Day told BBC Science's Horizon programme: "This event would be so huge that it would affect not only the people on the island but people way over on the other side of the Atlantic Ocean - people who've never heard of La Palma.
Day's latest work on the subject has been published in the Journal of Volcanology and Geothermal Research.
On the back of this work, the Geological Society of London is to write to the UK science minister, Lord Sainsbury, to make him aware of the dangers posed by so-called mega-tsunami in the Atlantic.
The society hopes he will take the issue as seriously as he has the threat from asteroid strikes.
Scientists have known of the destructive power of tsunami - huge tidal waves - for many centuries. As recently as 1998, over 2,000 people were killed by a large wave hitting the coast of Papua New Guinea.
This was caused by an offshore earthquake. But researchers believe far bigger phenomena can be created by giant landslides.
The largest wave in recorded history, witnessed in Alaska in 1958, was caused by the collapse of a towering cliff at Letuya Bay. The resulting wave was higher than any skyscraper on Earth and gouged out soil and trees to a height of 500 metres (1,640) feet) above sea level.
Geological studies have found evidence of giant landslides elsewhere in the world such as Hawaii, the Cape Verde Islands and Reunion in the Indian Ocean.
Dr Day has identified dozens of volcanic vents in the Cumbre Vieja volcano that have been formed by successive eruptions over the past 100,000 years.
He thinks water trapped between dykes of impermeable rock could create pressures that eventually lead to the western flank of the mountain falling away during some future eruption.
Hermann Fritz, of the Swiss Federal Institute of Technology, which has equipment to model waves created by landslides, said: "If the Cumbre Vieja were to collapse as one single block, it would lead to a giant mega-tsunami with an initial wave height of 650 metres.
"It would have a wavelength of 30 to 40 kilometres (18 to 25 miles) travelling westwards across the Atlantic at speeds up to 720 km/h (450 mph) towards America."
But researchers caution that such a catastrophe may not occur for many decades.
"There could be five more summit eruptions of the Cumbre Vieja before the western flank collapses," said Professor Bill McGuire, of the Benfield Greig Hazard Research Centre.
"There could be 10 or there could be 20 - we simply don't know. But put it this way: if I was living in Miami or New York and I heard that the Cumbre Vieja was erupting, I would keep a very close eye on the news."
Now consider this passage from the New International Version of the Bible (Luke 21), under the heading "Signs of the End of the Age:"
There will be signs in the sun, moon, and stars. On the Earth, nations will be in anguish and perplexity at the roaring and tossing of the sea. Men will faint from terror, apprehensive of what is coming on the world, for the heavenly bodies will be shaken. At that time they will see the Son of Man coming in a cloud with power and great glory. When these things begin to take place, stand up and lift up your heads, because your redemption is drawing near.
Tsunamis cause the sea to begin "tossing" when they mound up over the shallow continental shelf as they move toward shore. And they often cause "roaring" when they begin to overtop the coastline itself.
What do the Edgar Cayce readings say about the possibility of tsunamis along Atlantic shorelines? In a word, nothing. But we must remember that nobody ever asked. And like many potentially unbelievable subjects in Cayce's time, such as men landing on the moon, the readings are mute because no one ever asked about the possibility. However, a Cayce reading does mention that "inundations" from earthquakes will affect the coast of southern California, after "greater activities" in the volcanoes Vesuvius or Pelee. Such inundations would come from two main sources: undersea "landslides offshore of southern California and undersea landslides in the Hawaiian Islands.
Returning to the threat to Atlantic shores from tsunamis originating in the Canary islands, note that six geoscientists have just published a paper on the subject that indicates that this threat is much greater than inferred by previous studies. Sebastian Krastel And Others (Jour. Geophysical Research, v. 106, no. B3, 3110/2001) surveyed the submarine flanks of the Canary islands with the GLORIA long-range side-scan sonar system, bathymetric multibeam systems, and sediment echo sounders. They identified twelve geologically young (less than two million years old) giant landslides, and several older ones. Most slides were on the flanks of La Palma, E1 Hierro, and Tenerife. The ages of the five youngest slides range from 13 to possibly 536 thousand years old. The estimated volumes of these slides are huge, ranging between 25 to 1000 cubic kilometers (16-620 cubic miles). The destruction to Atlantic shores rendered by the tsunamis generated by these landslides must have been tremendous. If the Cayce readings' predictions about pole shift and Earth changes come true, it seems quite probable that there will again be mega tsunami in the future of the coastal communities of the Atlantic. Two of the main sources of such tsunamis will be the Hawaiian ridge and the Canary islands. But many other tsunami sources from former or potential underwater landslides have recently been identified. Among these are 1) the giant tsunami waves that hit Scotland about 7,000 years ago due to an underwater landslide off Storegga, southwest Norway; 2) the colossal wave that smashed Papua New Guinea's coast on `17 July 1998; 3) a tsunami that hit Puget Sound 1000-1100 years ago; 4) a series of three slides - perhaps triggered by earthquakes - that generated catastrophic tsunamis 110, 450, and 1,210 thousand years ago off southern Oregon; and 5) a giant landslide off Tahiti that undoubtedly generated some enormous tsunamis some 650 to 850 years ago.
Is it any wonder that, as Christ said, On the Earth, nations will be in anguish and perplexity at the roaring and tossing of the sea?
Continued...