Mathilda’s Weird World Weblog

October 25, 2008

A very British tsunami, 1607

Filed under: Drowned cities, strange but true — Tags: , — mathilda37 @ 3:31 pm

Not well known, is that in January 1607 an 8m high tsunami swept up the Severn estuary on the South West coast of England, killing about 2,000 people. A plaque in a church marks the high water mark, and reads:

“An inundation of the sea water by overflowing and breaking down the Sea banks; happened in this Parish of Kingstone-Seamore, and many others adjoining; by reason whereof many Persons were drown’d and much Cattle and Goods, were lost: the water in the Church was five feet high and the greatest part lay on the ground about ten days. WILLIAM BOWER”

Never assume that these things happen ‘in other places’. Link. All coasts are vulnerable.

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Killer tsumani in the Ancient Mediterranean

Filed under: Atlantis, Drowned cities — Tags: — mathilda37 @ 3:22 pm

Link

Tsunamis are known to destabilize soft marine sediments, the team notes, leaving telltale coverings of clay deposits after they reach land.

These deposits identify Mount Etna as the source of the tsunami and discount other possible causes, such as an asteroid strike or an undersea earthquake, the team says.

 The researchers also speculate that a Neolithic village just off the coast of present-day Israel was hit by the tsunami.

The well-preserved Atlit-Yam settlement, which due to altered sea levels today lies submerged, “shows evidence of a sudden abandonment” 7,000 to 8,000 years ago, the researchers write.

These signs include a pile of gutted fish that had been processed and then “stored for future consumption,” which was discovered buried under a layer of clay.

Further research by the Pisa-based team will investigate whether secondary tsunamis were set off by the sediment flows triggered by the initial tsunami from the Mount Etna collapse.

Pareschi said the probability of a new big collapse on Etna is low, but she added, “the eastern sector of the volcano is sliding toward the sea, and we have to understand very well the triggering mechanisms.”

If the Etna tsunami had happened today, she said, the impact would be catastrophic, because the eastern Mediterranean coast is so densely populated.

(Read “Etna Volcano Becoming Dangerous, Experts Warn” [February 6, 2003].)

Some ten percent of tsunamis worldwide occur in the Mediterranean.

The most recent volcano-triggered tsunami was caused by a landslide on the Italian island of Stromboli in the Tyrrhenian Sea in 2002.

The volume of the landslide “was however a thousand times smaller than the Mount Etna one,” Pareschi said.

A tsunami early warning system is currently being developed for the Mediterranean and the northeastern Atlantic. Due to become operational in December 2007, it will form part of a global tsunami warning system coordinated by the United Nations Educational, Scientific and Cultural Organization (UNESCO).

The measure follows in the wake of the devastating Indian Ocean tsunami, caused by an earthquake in December 2004, which struck coastlines with little or no warning.

Pareschi says the ancient Etna tsunami would have been comparable with the 2004 event, which claimed around 275,000 live.

I got caught in a very minor tsunami in the Med about ten years ago. When in the water, a big wave just surged right up the beach and unceremoniously dumped us all onto the sand. A bit scary, but not more than a half a metre high. The only thing to distinguish it from a big wave was the drawback and the fact it surged right up the beach. All this reading about tsunamis makes me edgy about living half a male from the sea on a dead flat piece of coast.

The theory being knocked around at present is that the melting ice at the end of the ice age caused mega tsunamis because the shifting weight triggered earthquakes, that started the tsunamis. This would really have put a dent in any civillisation that was trying retreating from rising sea levels. The regular tsunamis might explain why there’s a big stone ships achor half way up a big hill in the near east too.

October 24, 2008

Mega tsunamis strike ‘every thousand years’

Filed under: Atlantis, Drowned cities — Tags: , , — mathilda37 @ 4:53 pm

Well technically, as an average. We’ve had ten in a ten thousand year period.

 Mega-Tsunami Hit Earth 10,000 Years Ago;

Washington, D.C. — Scientists from Australia, New Zealand and the United States have come up with evidence of massive objects having struck the Earth’s oceans thousands of years ago, causing tsunamis that dwarf the ones experienced in recent times.

There have been up to 10 such impacts in the past 10,000 years, claimed Australian geomorphologist Ted Bryant of the University of Wollongong, Assistant Professor Dallas Abbott from the Lamont-Doherty Earth Observatory at Columbia University and New Zealand-based tsunami expert Dr Mauri McSaveney of GNS Science.

Bryant was quoted by ABC Online as saying that the mega-tsunamis of yore were at least 10 times bigger than the December 26, 2004 Asian tsunami.

“Aceh (in Indonesia) was a dimple compared to what we’re looking at,” says Bryant, who used satellite images from Google Earth to identify inland dunes in the shape of arrowheads that he says are signs of the mega-tsunamis.

The tsunamis would have displaced marine deposits containing marine fossils, he says, dumping them inland as ‘chevron’ dunes.

“We’ve found that chevrons are everywhere, everywhere around the world’s coasts,” he says.

Abbot used sea surface altimetry, which measures the height of the sea surface to get an image of the seabed, to identify possible underwater craters, which could be evidence of the impact that caused the tsunamis.

Bryant says Abbot also looked for melted material in cores from the seabed around the craters to confirm impacts caused them.

Bryant says chevrons about 4800 years old around the Indian Ocean are associated with a 29-kilometre wide impact crater located thousands of kilometres to the southeast of Madagascar.

Bryant says other evidence of a mega-tsunami as recently as 500 years ago has been found on the eastern coast of Australia.

None of the research has been published but some of it will be presented at an American Geophysical Union meeting in San Francisco next month

However, Earth scientist Professor Richard Arculus of the Australian National University and marine sediment specialist Dr Bradley Opdyke believe that more evidence is required to corroborate this view.

They, however, accept that Bryant’s claims are “perfectly plausible”, but need substantiation. (ANI)

If you were wondering were all the flood myths come from, there’s your answer..

It’s possible that mega tsunamis could totally destroy coastal towns beyond the point of archeaological reconstruction.

Noah’s flood; dated to May 10th, 2807 B.C.

Filed under: Atlantis, Drowned cities — Tags: , — mathilda37 @ 4:48 pm

At the southern end of Madagascar lie four enormous wedge-shaped sediment deposits, called chevrons, that are composed of material from the ocean floor. Each covers twice the area of Manhattan with sediment as deep as the Chrysler Building is high.

On close inspection, the chevron deposits contain deep ocean microfossils that are fused with a medley of metals typically formed by cosmic impacts. And all of them point in the same direction — toward the middle of the Indian Ocean where a newly discovered crater, 18 miles in diameter, lies 12,500 feet below the surface.

The explanation is obvious to some scientists. A large asteroid or comet, the kind that could kill a quarter of the world’s population, smashed into the Indian Ocean 4,800 years ago, producing a tsunami at least 600 feet high, about 13 times as big as the one that inundated Indonesia nearly two years ago. The wave carried the huge deposits of sediment to land.

Most astronomers doubt that any large comets or asteroids have crashed into the Earth in the last 10,000 years. But the self-described “band of misfits” that make up the two-year-old Holocene Impact Working Group say that astronomers simply have not known how or where to look for evidence of such impacts along the world’s shorelines and in the deep ocean.

Scientists in the working group say the evidence for such impacts during the last 10,000 years, known as the Holocene epoch, is strong enough to overturn current estimates of how often the Earth suffers a violent impact on the order of a 10-megaton explosion. Instead of once in 500,000 to one million years, as astronomers now calculate, catastrophic impacts could happen every 1,000 years.

The researchers, who formed the working group after finding one another through an international conference, are based in the United States, Australia, Russia, France and Ireland. They are established experts in geology, geophysics, geomorphology, tsunamis, tree rings, soil science and archaeology, including the structural analysis of myth. Their efforts are just getting under way, but they will present some of their work at the American Geophysical Union meeting in December in San Francisco.

This year the group started using Google Earth, a free source of satellite images, to search around the globe for chevrons, which they interpret as evidence of past giant tsunamis. Scores of such sites have turned up in Australia, Africa, Europe and the United States, including the Hudson River Valley and Long Island.

When the chevrons all point in the same direction to open water, Dallas Abbott, an adjunct research scientist at Lamont-Doherty Earth Observatory in Palisades, N.Y., uses a different satellite technology to look for oceanic craters. With increasing frequency, she finds them, including an especially large one dating back 4,800 years.

So far, astronomers are skeptical but are willing to look at the evidence, said David Morrison, a leading authority on asteroids and comets at the NASA Ames Research Center in Mountain View, Calif. Surveys show that as many as 185 large asteroids or comets hit the Earth in the far distant past, although most of the craters are on land. No one has spent much time looking for craters in the deep ocean, Dr. Morrison said, assuming young ones don’t exist and that old ones would be filled with sediment.

Astronomers monitor every small space object with an orbit close to the Earth. “We know what’s out there, when they return, how close they come,” Dr. Morrison said. Given their observations, “there is no reason to think we have had major hits in the last 10,000 years,” he continued, adding, “But if Dallas is right and they find 10 such events, we’ll have a real contradiction on our hands.”

Peter Bobrowsky, a senior research scientist in natural hazards at the Geological Survey of Canada, said “chevrons are fantastic features” but do not prove that megatsunamis are real. There are other interpretations for how chevrons are formed, including erosion and glaciation. Dr. Bobrowsky said. It is up to the working group to prove its claims, he said.

William Ryan, a marine geologist at the Lamont Observatory, compared Dr. Abbott’s work to that of other pioneering scientists who had to change the way their colleagues thought about a subject.

“Many of us think Dallas is really onto something,” Dr. Ryan said. “She is building a story just like Walter Alvarez did.” Dr. Alvarez, a professor of earth and planetary sciences at the University of California, Berkeley, spent a decade convincing skeptics that a giant asteroid wiped out the dinosaurs 65 million years ago.

Ted Bryant, a geomorphologist at the University of Wollongong in New South Wales, Australia, was the first person to recognize the palm prints of mega-tsunamis. Large tsunamis of 30 feet or more are caused by volcanoes, earthquakes and submarine landslides, he said, and their deposits have different features.

 Deposits from mega-tsunamis contain unusual rocks with marine oyster shells, which cannot be explained by wind erosion, storm waves, volcanoes or other natural processes, Dr. Bryant said.

“We’re not talking about any tsunami you’re ever seen,” Dr. Bryant said. “Aceh was a dimple. No tsunami in the modern world could have made these features. End-of-the-world movies do not capture the size of these waves. Submarine landslides can cause major tsunamis, but they are localized. These are deposited along whole coastlines.”

For example, Dr. Bryant identified two chevrons found over four miles inland near Carpentaria in north central Australia. Both point north. When Dr. Abbott visited a year ago, he asked her to find the craters.

To locate craters, Dr. Abbott uses sea surface altimetry data. Satellites scan the ocean surface and log the exact height of it. Underwater mountain ranges, trenches and holes in the ground disturb the Earth’s gravitational field, causing sea surface heights to vary by fractions of an inch. Within 24 hours of searching the shallow water north of the two chevrons, Dr. Abbott found two craters.

Not all depressions in the ocean are impact craters, Dr. Abbott said. They can be sink holes, faults or remnant volcanoes. A check is needed. So she obtained samples from deep sea sediment cores taken in the area by the Australian Geological Survey.

The cores contain melted rocks and magnetic spheres with fractures and textures characteristic of a cosmic impact. “The rock was pulverized, like it was hit with a hammer,” Dr. Abbott said. “We found diatoms fused to tektites,” a glassy substance formed by meteors. The molten glass and shattered rocks could not be produced by anything other than an impact, she said.

“We think these two craters are 1,200 years old,” Dr. Abbott said. The chevrons are well preserved and date to about the same time.

Dr. Abbott and her colleagues have located chevrons in the Caribbean, Scotland, Vietnam and North Korea, and several in the North Sea.

Hither Hills State Park on Long Island has a chevron whose front edge points to a crater in Long Island Sound, Dr. Abbott said. There is another, very faint chevron in Connecticut, and it points in a different direction.

Marie-Agnès Courty, a soil scientist at the European Center for Prehistoric Research in Tautavel, France, is studying the worldwide distribution of cosmogenic particles from what she suspects was a major impact 4,800 years ago.

But Madagascar provides the smoking gun for geologically recent impacts. In August, Dr. Abbott, Dr. Bryant and Slava Gusiakov, from the Novosibirsk Tsunami Laboratory in Russia, visited the four huge chevrons to scoop up samples.

Last month, Dee Breger, director of microscopy at Drexel University in Philadelphia, looked at the samples under a scanning electron microscope and found benthic foraminifera, tiny fossils from the ocean floor, sprinkled throughout. Her close-ups revealed splashes of iron, nickel and chrome fused to the fossils.

When a chondritic meteor, the most common kind, vaporizes upon impact in the ocean, those three metals are formed in the same relative proportions as seen in the microfossils, Dr. Abbott said.

Ms. Breger said the microfossils appear to have melded with the condensing metals as both were lofted up out of the sea and carried long distances.

About 900 miles southeast from the Madagascar chevrons, in deep ocean, is Burckle crater, which Dr. Abbott discovered last year. Although its sediments have not been directly sampled, cores from the area contain high levels of nickel and magnetic components associated with impact ejecta.

Burckle crater has not been dated, but Dr. Abbott estimates that it is 4,500 to 5,000 years old.

It would be a great help to the cause if the National Science Foundation sent a ship equipped with modern acoustic equipment to take a closer look at Burckle, Dr. Ryan said. “If it had clear impact features, the nonbelievers would believe,” he said.

But they might have more trouble believing one of the scientists, Bruce Masse, an environmental archaeologist at the Los Alamos National Laboratory in New Mexico. He thinks he can say precisely when the comet fell: on the morning of May 10, 2807 B.C.

Dr. Masse analyzed 175 flood myths from around the world, and tried to relate them to known and accurately dated natural events like solar eclipses and volcanic eruptions. Among other evidence, he said, 14 flood myths specifically mention a full solar eclipse, which could have been the one that occurred in May 2807 B.C.

Half the myths talk of a torrential downpour, Dr. Masse said. A third talk of a tsunami. Worldwide they describe hurricane force winds and darkness during the storm. All of these could come from a mega-tsunami.

Of course, extraordinary claims require extraordinary proof, Dr. Masse said, “and we’re not there yet.”

Link

So it would seem there are reasons behind the ubiquitous ‘flood myths’. I’m particularly interested in the date 2807 BC. This could explain the biblical myth, as this is compatible with a early Judaic era (when they were polytheists) and could easily have made a big impression on their religious beliefs.

Burckle crater= red dot.

This information is comaptible with the dating of the Sumerian flood layer from between 2750 and 2900 BC. The great flood is described thus..

All the windstorms, exceedingly powerful,
Attacked as one,
At the same time, the flood sweeps over the cult-centers.
After, for seven days,
the flood sweeps over the cult centers.
After, for seven days and seven nights,
The flood had swept over the land,
And the huge boat had been tossed
About by the windstorms on the great waters,

Sounds like a mega tsunami with simultaneous heavy rainstorms. It seems pretty clear from this text that the rain didn’t cause the flood, but happened at the same time.

Tsunami clue to Atlantis found

Filed under: Atlantis, Drowned cities — Tags: , — mathilda37 @ 4:14 pm

Tsunami clue to ‘Atlantis’ found 
 
A submerged island that could be the source of the Atlantis myth was hit by a large earthquake and tsunami 12,000 years ago, a geologist has discovered.


Spartel Island now lies 60m under the sea in the Straits of Gibraltar, but some think it once lay above water.

The finding adds weight to a hypothesis that the island could have inspired the legend recounted by the philosopher Plato more than 2,000 years ago.

Evidence comes from a seafloor survey published in the journal Geology.

Marc-André Gutscher of the University of Western Brittany in Plouzané, France, found a coarse-grained sedimentary deposit that is 50-120cm thick and could have been left behind after a tsunami.

Dr Gutscher said that the destruction described by Plato is consistent with a great earthquake and tsunami similar to the one that devastated the city of Lisbon in Portugal in 1755, generating waves with heights of up to 10m.

 Some think the Atlantis legend was inspired by real events
The thick “turbidite” deposit results from sediments that have been shaken up by underwater geological upheavals.

It was found to date to around 12,000 years ago – roughly the age indicated by Plato for the destruction of Atlantis, Dr Gutscher reports in Geology.

Spartel Island, in the Gulf of Cadiz, was proposed as a candidate for the origin of the Atlantis legend in 2001 by French geologist Jacques Collina-Girard.

It is “in front of the Pillars of Hercules”, or the Straits of Gibraltar, as Plato described. The philosopher said the fabled island civilisation had been destroyed in a single day and night, disappearing below the sea.

Sedimentary records reveal that events like the 1755 Lisbon earthquake occur every 1,500 to 2,000 years in the Gulf of Cadiz.

But the mapping of the island carried out by Dr Gutscher failed to turn up any manmade structures and also showed that the island was much smaller than previously believed.

This could make it less likely that the island was inhabited by a civilisation

Personally I’d suspect either a massive earthquake in the Canaries region or an asteroid splashing down in the Atlantic as the cause.

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