[plschwartz]

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August 10, 2004

Scientists fear volcano disaster as checks cut
By Mark Henderson, Science Correspondent

A VOLCANO in the Canary Islands that could kill millions of people when it next erupts is no longer being properly monitored because of budget cuts, scientists said yesterday.

The Cumbre Vieja volcano on La Palma presents a severe threat to cities all around the North Atlantic, as a future eruption could trigger a “mega-tsunami”.

Such a disaster would be one of the worst in recorded history, devastating the coasts of North America, Brazil, the Caribbean, North Africa and Atlantic Europe. Hundreds of millions of people would have to be evacuated, and the total cost would run into trillions of pounds.

Europe would be protected from the fiercest force by the position of the other Canary Islands, but the tsunami would still bring 33ft (10m) waves to Lisbon and La Coruña within three hours. It would reach Britain after six hours, with waves rearing up to 40ft.

Between nine and twelve hours later, it would reach the Americas, laying waste the eastern seaboard of the United States with waves at more than 165ft — higher than Nelson’s Column. Boston, New York and Miami would be destroyed and Caribbean islands swamped.

Cumbre Vieja is a particular danger because the mountain is unstable and will eventually break apart under the strain of an eruption. While this is not thought to be imminent, when it happens it will deposit a slab of rock twice the size of the Isle of Man into the ocean, starting a mega-tsunami, a huge tidal wave.

Early warning of an eruption would be critical to minimising the number of lives lost, yet politicians from the countries that would be affected are not taking the threat seriously, experts said.

The Spanish Government has withdrawn funding for a surveillance project, and seismic monitoring of Cumbre Vieja has essentially been abandoned. As a result, there is unlikely to be time to evacuate cities in the tsunami’s path in the event of a dangerous eruption.

Bill McGuire, of the Benfield Hazard Research Centre in London, who has studied Cumbre Vieja in detail, said that the cost of proper monitoring would be only a few hundred thousand pounds.

“This is peanuts, but no one is taking this seriously,” he said. “What we need now is an integrated volcanic monitoring system to give maximum warning of a coming eruption.

“The US Government must be aware of the La Palma threat. They should certainly be worried, but they have not been in contact. Governments change every four to five years and they’re not interested in these things, which might not happen within their terms of office.

“The problem is that with just a few seismometers on the mountain, as we have at the moment, we may not get the notice we need of an eruption. No volcano erupts without warning signs, and we could get one to two weeks’ notice if surveillance is in place.”

The situation highlights how poorly the world is prepared for “global geophysical events” or “gee-gees”, Dr McGuire said. These disasters — huge volcanic eruptions, asteroid impacts and earthquakes in economically critical spots such as Tokyo — occur very infrequently, but would have a worldwide impact.

A volcanic eruption of 8 on the disaster scale takes place roughly every 50,000 years — and the last one, at Toba, was 73,500 years ago. It would produce enough ash to bury the British Isles to a depth of 12ft, and would collapse roofs more than 900 miles away.

“The Toba eruption had 1,000 times the force of Mount St Helens,” Dr McGuire said. “It would change the climate with the potential to cause global agricultural collapse. Yet there has been no planning for how we would cope.

“We need to identify the potential threats and monitor them, but there are about 3,000 active volcanoes on the planet and we’re monitoring about 150. Obviously, terrorism is seen as the big threat at the moment, but it’s a tiny pinprick compared with the festering boil of gee-gee disasters.”

Cumbre Vieja normally erupts at intervals of 20 to 200 years. The last big eruption was in 1971. The next eruption may not start a tsunami, but it is certain to happen in the end. Within five minutes, a dome of water a mile high would form and then collapse, before the mega-tsunami fanned out in every direction at up to 500mph. The only way to mitigate catastrophe would be to have sufficient warning to stage the largest evacuation in human history. This also requires planning and research, not least to guard against a false alarm that sparked mass panic. “We can be almost certain there will be false alarms, and we have to consider how to handle that,” Dr McGuire said. But he added: “This is a certain event. It may not happen the next time Cumbre Vieja erupts, but it will happen and we will have to deal with it.”

[twotugs]

I saw a show on Discovery Channel or A&E or some such channel a few weeks ago that covered the La Palma potential, and was interested enough to look around online for more info. The danger seems real, but certainly not imminent.

Here's an older site that plays down the situation...

http://personal.telefonica.terra.es/...gatsunami.html

...and a BBC article that's more recent:

http://news.bbc.co.uk/1/hi/sci/tech/3963563.stm

[Wet Chicken]

Originally Posted by plschwartz

A VOLCANO in the Canary Islands that could kill millions of people when it next erupts is no longer being properly monitored because of budget cuts

This is very irresponsible

[alex_holker]

While it might be important to keep an eye on this potential threat, people shouldn't neccessarily be focussing on this and neglecting other threats and duties. It just seems a bit like closing the gate after the horse has bolted.

Alex

[plschwartz]

Dr. Crane

Jason Kordelski

Analysis Paper



The Mega-Tsunami



In 1953 Lituya Bay, Alaska, became the object of interest to a pair of geologists on the never-ending search for viable petroleum deposits. The two of them noticed that the sediments layered against the steep cliffs surrounding the bay were concurrent with deposits that could have been made only by gigantic waves breaking against the shoreline. The geologists were amazed. These were no ordinary wave deposits. These were not even ordinary tsunami deposits. These deposits suggested a wave height of more than 100 metres (300 feet). But the best was yet to come. In 1958, an earthquake with a magnitude of 8.0 occurred along the Alaskan Fairweather Fault, which runs beneath the northwestern spur of Lituya Bay (Bernard, 1991). A massive volume of rock alongside the Gilbert Inlet sloughed off into the water, creating a splash 1720 feet in height on the opposite shore that destroyed acres of coniferous vegetation. Water displacement resulting from the rockslide propagated a 100 foot tsunami across the bay towards the mouth and the Gulf of Alaska (Bernard). Five square miles of land surrounding the bay were inundated, and the tsunami moved inland as far as 3600 feet. Two boaters attempting to outrun the wave in their ship and make it to open water were killed. Other fishermen rode the crest of the wave in their motorboats and survived, even as they were

tossed across the pine trees when the tsunami forced its way up the cliffs near the mouth of the bay (Bernard).

This is but one example of a localized tsunami incident that has occurred in recent times. In 1992, a tsunami inundated and caused great destruction in Nicaragua on the west coast of South America (Dudley, 1997). In 1993, a tsunami submerged an entire peninsula in Hokkaido, Japan (Dudley). In 1994, tsunamis occurred along the coasts of East Java, Mindoro, and Kuril in the Eastern Pacific (Dudley). In 1998 a large tsunami struck Papau New Guinea and destroyed a village of tribesmen and their families (Dudley). And the “Big One,” so named by scientists, is on its way. Conditions are arising in the world around us that will eventually result in a colossal destructive tsunami that could possibly affect major nations and cities along the Atlantic Ocean. The volcanic island La Palma in the Canaries off of northern Africa is poised to send a massive wave to the US Eastern Seaboard. The eastern coastline of North America could slide into the sea as it has done in the past, smearing Europe clean of civilization with the resulting tsunami. And the ever-present bolide tsunamis, those created from impacts of extra-terrestrial objects, are as unavoidable as they are unpredictable. There is no question that one or more of these scenarios will occur sometime in the future, perhaps the near future. The question is, are we prepared?

Predicting the future, particularly when it comes to geology, has a lot to do with understanding the past. Only one mega-tsunami has occurred within the annals of recorded human history, and from this event we can discern valuable information. In 1650 B.C. the Aegean Sea saw a spectacular volcanic eruption on the island of Thera (Soloviev, 2000).

The volcano Santorini, following a great period of unrest, exploded in such violence that the consequences would dwarf those seen during Krakatau’s detonation more than two millennia later. The island of Thera was instantly shattered and vaporized. Pyroclastics were rocketed 26 miles into space (Soloviev). A crater thousands of metres deep was scoured into the seabed, only to have the water spill in and explode into the atmosphere as it touched the hot magma beneath. The outskirts of Thera that were spared, slivers of land, were buried under hundreds of feet of tephra and volcanic ash. Pyroclastics from Santorini have even been discovered in sediments from Greenland (Soloviev). Needless to say, the civilization upon the island at that time, believed by some to be the lost ‘continent’ of Atlantis, was wiped out. This was not the end, however. A massive tsunami was generated, far greater in size than any other tsunami reported from then up to the present. The water displacement produced by the initial eruption, the deluge into the chasm, and the resulting explosion due to internal heat contacting with water propagated a tsunami across the Aegean Sea (Soloviev).

Some scientists believe that many of the islands in the Aegean Sea were completely submerged, although islands at higher latitudes such as Syros and Naxos would have shielded the northern Aegean from the tsunami wave energy (Soloviev). The greatest destruction, though, occurred along the island of Crete in the northern Mediterranean.

This island was the capital of the Minoan empire, which ranged across the Aegean Sea. 1650 B.C. saw the instantaneous eradication of all human life on Crete, conveniently situated south of Thera and the only target for the southern flank of any generated tsunami coming from the Aegean (Soloviev). Sediments along the northern coast of Crete are loaded with an unusually high amount of salt, concurrent with the inundation of a major wave train. The width of the island itself was enough to ensure that the brunt of the tsunami force would focus against this face of the island, geographically where the temples and palaces of the Minoans were erected (Soloviev).

The incident on Thera teaches us that earthquakes are not the only progenitors of tsunamis. The amount of displaced water necessary to create a major tsunami is often not concurrent with undersea tremors. Rather, tectonic events such as landslides, bolide impacts, and volcanic eruptions produce the largest waves (Tinti, 1991). Earthquakes at or near the sea floor can causes a vertical displacement of several metres over an area of dozens of square kilometers, resulting in an average displacement around 1,000,000 cubic metres. A catastrophic coastal landslide, however, can deposit several billion cubic metres of material into the ocean. In Thera’s case, the instantaneous destruction of an entire island approximately 286 kilometers in area would have displaced as much water, not to mention the resulting crater the sea rushed to fill in (Soloviev, 1991). Bolide tsunamis produce a water displacement nearly equal in volume to the extraterrestrial object that strikes the ocean, although a good amount of water is vaporized upon impact and injected into the atmosphere (Tinti, 1991).

The general trend for the mega-tsunami depends on water displacement. The greater the volume of water displaced, the larger the mega-tsunami. Mega-tsunami are greatly affected by the shape of the ocean floor, nevertheless, and like other tsunamis have their breaking heights determined by coastal bathymetry (Dudley, 1988). A coastal community erected on a segment of continental shelf where the ocean floor harbors a steep slope will experience a less devastating tsunami; the wave train has no time to ‘gain its footing’ along the bottom and build itself up into a series of succeeding crests (Dudley). In an opposite fashion, a shallow bathymetry allows the tsunami wave energy to slowly build into wave crests, which then move closer together as the shallow water slows the wave train down. As a result, a tsunami of greater strength reaches shore. Coastal communities built in these regions are most at risk from a mega-tsunami, as they are susceptible to minor waves and would stand no chance against a wave produced by water displacement several million times greater than the average tsunami. A mega-tsunami produced in the Pacific Ocean could cause 300 foot waves to hit Hawaii while 1 foot waves arrive in California (Dudley). The shape of the ocean floor is an overlooked yet constant decider of wave heights. In the same fashion, certain objects or obstacles can shield areas of coastline from the devastation of a mega-tsunami. Island arcs such as the Aleutians can absorb tsunami wave energy, and coral reefs a significant distance away from shore can prevent large waves from striking the coast (Dudley). However, if a mega-tsunami is large enough and the result of a great enough displacement of water, nothing will stop it from striking shore. Mega-tsunami in the past have reached projected heights of 3000 feet, the progress of which no amount of coral can halt.

Currently, there are several causes of concern for scientists who study tsunamis and tsunamigenic activity. One lies less than 500 kilometers off the coast of Northern Africa, the island of La Palma in the Canaries. Cumbre Vieja, the active volcano located on the southern spur of the island, is laterally fractured to a severe enough extent that any volcanic eruption or tectonic activity in the region could cause the entire western flank of the mountain to collapse and slough off into the sea (benfieldhrc.org, 2000). The fracture itself is the result of years of seismic activity that have cut the volcano into roughly two chunks of earth, with one constantly being tugged by gravity towards the ocean. Should a minor earthquake or volcanic disturbance put any more stress on this fracture, the mountain will split and collapse, sending more than 500 cubic kilometers (125,000,000,000 cubic meters) of material into the Atlantic (benfieldhrc.org). A fan of debris will spread out onto the sea floor 60 kilometers from the coastline at a speed of 350 km/h. The energy released by the avalanche will equal that of the electricity consumption of the United States for six months (benfieldhrc.org). The result will be a tsunami of catastrophic proportions.

Dr. Simon Day of the Benfield Greig Hazard Research Centre at UCL and Dr. Steven Ward of the University of California predict that the initial displacement will form a dome of water dozens of kilometers wide and around 900 metres in height (benfieldhrc.org). After dissipating, the dome will have propagated a tsunami wave train across the Atlantic. The West African shore and Morocco will be first hit with waves 100 metres in height. Coastal Brazil will follow with waves 40 metres tall. The Caribbean and the eastern shores of Florida will mark the end of the tsunami’s journey, but only after

standing against waves 50 metres in height eight to nine hours after the collapse of the volcano (benfieldhrc.org).

Aside from the obvious problems waves 300 feet high can cause to populated coastal regions like Morocco, the process of inundation must be examined. Inundation of a tsunami is described as the distance inland the tsunami waves actually travel. While it is true that many lives are lost and buildings leveled by the brute force of the wave crest arriving at shore, a good amount of the destruction associated with tsunami are the result of extensive inundation and flooding farther inland. As with any ocean wave, the tsunami will retreat into the ocean after it moves as far as possible inland, as the consequence of either gravity or another tsunami wave moving close to shore. This drawback of the ocean water ultimately sucks all objects in the flooded region towards the sea, including people (Dudley, 1997). Inundation is severe for coastal communities that do not rise quickly above sea level beyond the shoreline.

This is where the most intriguing topographical fact concerning the state of Florida comes into play. More than 50% of this state is less than 10 metres above sea level, especially around the coastal regions. This means that, should sea level in the world’s oceans increase by 10 metres, roughly one half of Florida would be totally submerged by water. What then happens when the sea level around Florida is raised by 50 metres? The tsunami that arrives will deluge the entire eastern coastline of the Sunshine State, then move inland for quite a significant distance, given the altitude of Florida’s low-lying coastal regions. West Palm Beach, Cape Canaveral, Orlando, and St. Augustine are the major seaside cities that will face the brunt of the tsunami wave’s energy. Florida will be the most affected state due to the mega-tsunami, but waves will arrive all along the Eastern Seaboard of the United States with an average height of 10 metres, with aberrant heights in enclosed bodies such as the Chesapeake Bay.

Doctors Day and Ward conclude that the eruption, earthquake, or deformation in Cumbre Vieja that will result in the lethal landslide are a cause of concern but not at this very moment in time. Such a landslide would be preceded by tectonic events for some weeks, giving ample time to enact evacuation protocols for the numerous threatened regions.

La Palma in the Canaries is not the only area under threat of a major landslide that could result in an Atlantic-wide mega-tsunami. This next threat is very much closer to home: the Eastern Seaboard, this time the cause and target of a disaster instead of merely the target. There are two scenarios that American scientists have been poking into for the last few years as tsunamigenic science in the Atlantic has come full circle. Evidence, locked in what was previously thought to be ordinary erosional deposits along the continental shelf, has come to light (Hebenstreit, 1997). The ocean waves constantly move against the shoreline and erode material from the continents that eventually is deposited in sediments along the continental shelf; this is a natural process. As a result, scientists assume that all sediment deposits on the shelf were formed from erosion. Recently, it has been discovered that many times during the life of the Atlantic Ocean, hundreds of miles of shoreline have broken off from the eastern U.S. and spilled into the sea (Hebenstreit). This is a scenario much like La Palma in the Canaries, but with a cause for greater concern. Volcanic Cumbre Vieja has a limit to how much material it can dump into the ocean. The Eastern Seaboard does not. Any major landslide on the east coast would not only destroy the civilization established upon that land, but cause a mega-tsunami of indescribable proportions to cross the Atlantic and rave every coastal community on the other side. Similarly, the landslide would deposit material at a distance from the coastline, thus displacing water at that distance and sending the mega-tsunami back towards the land it slid away from (Bryant, 2001). The east coast of the U.S. would be struck with a local mega-tsunami generated close to the shore and thus not susceptible to the loss of energy tsunamis that travel great distances are.

The second threat to the United States lies in submarine canyons. Submarine canyons are narrow, deep troughs usually raking through the continental shelf to the edges of the continental slope (Scientific American, 2000). These canyons are numerous off the coast of America, particularly the states North Carolina, New Jersey, and Virginia. Submarine canyons are sites of extreme instability, as they often collapse or contribute to the collapse of large regions of the continental shelf by halving regions and promoting the faulting of rocks (Scientific American). Such a crack is present off the coast of Cape Hatteras in North Carolina. Although the evidence appears to point to what ‘might’ happen rather than what ‘will,’ consider this: in 1929 an underwater landslide occurred off of Newfoundland, producing a tsunami that killed 51 people (Scientific American).

A further threat concerns trapped gases and liquids buried deep in sediments on the continental shelf. The east coast of the United States boasts many underwater kilometer-wide craters formed from the explosion of trapped gases in thick erosional deposits (Scientific American). Oil rigs have been destroyed by puncturing these pockets as the volatile gases rush to the surface. Moreover, waterlogged sediments and in some cases water pockets compressed by sediments have been discovered 150 miles off the coast of Atlantic City, New Jersey (Scientific American). Erosion or some form of tectonic disturbance could penetrate said pockets over time and cause a violent explosion of compressed material that may result in a massive amount of water displacement, and

thus a mega-tsunami thrown towards the Eastern Seaboard should the volume of these gases and liquids be great enough (Scientific American).

In most cases, however, the gas/liquid bubble scenario and the submarine canyon collapse would not displace enough water to propagate a mega-tsunami towards any coastline (Scientific American). Yet inevitably, the danger remains that a massive coastal landslide could dump many billions of cubic metres of material into the Atlantic Ocean, on a scale equal to that of Cumbre Vieja or perhaps greater (Scientific American). Consequently, a tsunami greater than any other in recorded history would undoubtedly strike Europe and Africa, as well as North America, leaving devastation in its wake.

While there has been much talk of destruction so far, no scenario can possibly compare to this tsunamigenic situation presented last, that of a bolide tsunami, a mega-tsunami produced by the impact of an extraterrestrial object such as an asteroid or comet into the oceans of Earth (Dudley, 1998). Evidence tells us that bolide mega-tsunami have occurred around the world at different periods in our planet’s history. In the year 1500 AD, coastal New Zealand was abandoned by its indigenous peoples (GSA, 2003). According to testaments of aboriginal legends, a great fireball was seen over the sea prior to the evacuation (GSA). Investigators who made the above connection went poking around in the eastern Tasman Sea, only to discover the remains of an impact crater on the

sea floor 20 kilometers in width and 128 meters in depth (GSA). Dredging turned up sediment deposits approximately 500 years old, judged by their depth (GSA). This fits in conjunction with the abandonment and the origin of the aboriginal legend. Similarly, tsunami runup deposits of sand were discovered 260 meters above sea level in Stewart Island, New Zealand (GSA). As the reader can interpret, the evidence suggests a bolide mega-tsunami 260 metres in height occurred in the Tasman Sea in the year 1500 AD, either causing the aborigines to abandon their homes or wiping them out.

The meteorite impact in the Yucatan peninsula right on the K-T boundary would have no doubt caused an enormous mega-tsunami to propagate across the Gulf of Mexico (Alvarez, 1997). Sand beds in Texas and other U.S. states have confirmed this theory (Alvarez). Estimates place the tsunami at a height of one kilometer (Alvarez). Any bolide mega-tsunami in the future could be much bigger. If the size of a bolide mega-tsunami is determined by the volume of the impacting bolide, then the larger the bolide, the large the mega-tsunami produced. Wave heights from an especially large bolide could reach more than several miles or kilometers in height (Alvarez). The devastation and inundation from such a bolide would be unimaginable.

The mega-tsunami is an extremely frightening phenomenon. Whether caused by landslides in conjunction with volcanic eruptions, landslides as a result of submarine canyons or faulting, exploding gases and liquids, or alien chunks of rock slamming into the world, the mega-tsunami is sure to be an extremely destructive event no matter what its progenitor might be. The wave height is massive, the inundation is great. While humans cannot intervene in most cases to stop such ocean waves from occurring, they can prepare. Worldwide efforts can be made to educate coastal communities, especially those in underdeveloped countries where knowledge is not particularly well-founded. The education of people concerning their tsunami or mega-tsunami threat is the greatest tool people can use against this natural disaster; by knowing the causes and effects, and knowing where and when to escape. The mega-tsunami may be unpreventable and

unstoppable, but wanton death at the hands of great waves is beneath us so long as we understand our foe. Humans have, in any case, a long time to wait and prepare for the next mega-tsunami.



References



Alvarez, Walter. Tyrannosaurus rex and the Crater of the Destiny. Princeton: Princeton

University Press, 1997.



Bernard, E. N., ed. Tsunami Hazard. Boston: Kluwer Academic Publishers, 1991.



Bryant, Edward. Tsunami: The Underrated Hazard. Cambridge: Cambridge University

Press, 2001.



“Did a Bolide Impact Cause Catastrophic Tsunamis in Australia and New Zealand?”

Geological Society of America. <http://gsa.confex.com/gsa> 9 November 2003



Dudley, Walter C., and Min Lee. Tsunami! Honolulu: University of Hawaii Press, 1988.



“Frequently Asked Questions.” Pacific Tsunami Museum. <http://www.tsunami.org>

10 October 2003



Hebenstreit, Gerald, ed. Perspectives on Tsunami Hazard Reduction. Dordrecht: Kluwer

Academic Publishers, 1997.



“Killer Waves on the East Coast?” Scientific American. <www.sciam.com> 10

November 2003



“Landslide Produced Tsunami Images.” Incorporated Research Institutions for

Seismology. <http://www.iris.washington.edu> 14 November 2003



“Mega Tsunami to Devastate US Coastline.” <http://www.benfieldhrc.org/Centre News>

13 November 2003



National Oceanic and Atmospheric Administration. Tsunamis Affecting Alaska 1737-

1996. Boulder: United States Department of Commerce, 1996.



National Oceanic and Atmospheric Administration. Tsunamis Affecting the West Coast

of the United States 1806-1992. Boulder: United States Department of

Commerce, 1993.



Soloviev, Sergey L., and Olga N. Solovieva. Tsunamis in the Mediterranean Sea: 2000

BC-2000 AD. Dordrecht: Kluwer Academic Publishers, 2000.



“The 1946 Aleutian Tsunami.” University of Southern California Tsunami Research

Group. <http://www.usc.edu/dept/tsunamis/alaska/1946/webpages> 9 October

2003



Tinti, Stefano, ed. Tsunamis in the World. Boston: Kluwer Academic Publishers, 1991.



Tsuchiya, Yo****o, ed. Tsunami: Progress in Prediction, Disaster Prevention and

Warning. Dordrecht: Kluwer Academic Publishers, 1995.



“Tsunami!” Geophysics Department, University of Washington. <http:www.geophys.

washington.edu/tsunami> 9 October 2003.

[plschwartz]

Anyway, what happened at Lituya was movement along the fault that runs from left to right in the above picture. If you pretend you're actually standing on the ridgetop looking out over the Bay (like the view in the above picture) the fault would be in the mountains behind you. The "movement in the fault", of course, is called an earthquake. The magnitude of the quake was about 8.3, although some sources say it was a 7.9, on the Richter Scale (a scale for measuring the magnitude, or amount of energy released, from an earthquake). Pretty awesome shaker. Well, shaker it was...it "shook" loose an estimated 40 million cubic yards of dirt and glacier from a mountainside at the head of the Bay, about where you're standing in the above picture. When the stuff went "kersploosh" into the water it created a massive wave that washed 1,720 ft/524m high over the headland in the right side of the above picture. You can see the damage to the trees that were growing on the headland when the wave washed over the top of it - there were no trees left...wiped 'em clean off. The picture at left gives you a closer view of the damage to the headland that the tidal waves caused.[quote]

Human Witnesses

There were three fishing boats anchored at the mouth of Lituya Bay on the day the awesome waves happened. That's the main reason we know it happened. There were human witnesses to the catastrophic event. Unfortunately, one of the boats was close to shore and the huge waves overtook it killing the two people on board. Amazingly, the other two boats "rode" the tidal waves as they washed from the source of the landslide and resonated around the bay, like water sloshing in a wash basin. The boaters watched in horror as the first enormous wave engulfed the small fishing boat and wiped everything in its path off the land, like wiping up crumbs with a kitchen sponge. If there had been a town or city on the shores of the bay everyone in it would have been killed. Fortunately, because it was an unpopulated area, the loss of life was minimal (although, the family of the victims hardly think that it was good fortune).

t "shook" loose an estimated 40 million cubic yards (30,000,000 cumeter) of dirt and glacier from a mountainside at the head of the Bay,

Cumbre Vieja, the active volcano located on the southern spur of the island, is laterally fractured to a severe enough extent that any volcanic eruption or tectonic activity in the region could cause the entire western flank of the mountain to collapse and slough off into the sea (benfieldhrc.org, 2000). The fracture itself is the result of years of seismic activity that have cut the volcano into roughly two chunks of earth, with one constantly being tugged by gravity towards the ocean. Should a minor earthquake or volcanic disturbance put any more stress on this fracture, the mountain will split and collapse, sending more than 500 cubic kilometers (125,000,000,000 cubic meters) of material

about 4000 times alaska landslide!

ActuallY I feel more threatened by this possibility then I did about being threatened by Saddams WMD. I would gladly divert some of the Iraq war money to demolishing this threat.
Maybe we could relocate the naval air practise from the island off puerto rico and get some use out of dropping bombs.

[MSM Hobbes]

Paul, good links and info. Have been watching this area, and others, for some time. As said, unfortunately, even the experts are at a loss to be to predict w/ any certainty the effect of any earthquake or other potential tsunami-originator to actually warn. Look at Hawaii in the mid-1900's: they had a warning system, but due to a perceived "crying wolf" syndrome, many people died needlessly cause they didn't take that warning seriously, cause during prior warnings, the tsunamis weren't nothing more than a 6" or maybe a 10-20' "wave".

[lizard]

Very interesting reading pl.

Concerning the impact off the Yucatan peninsula, I read somewhere that the tsunami wave generated would have been massive and forceful enough to reach the Canadian Rocky Mountains, All the way to the other side of the North American continent! I'm not 100% sure of this, but I think the enormous quantity of Dinosaur fossils found in Alberta were deposited there by the backwash of the wave!

Doing a little research on tsunami's, I came across a potential threat off Oregon. I had no idea....

Oregon geologists plot tsunami impact on the state's coastline
Published: January 1, 2005
By Lily Raff

The Bulletin

Scientists aren't wondering if Oregon will someday be hit by a massive earthquake and tsunami like the one that devastated nations around the Indian Ocean this week.

They are wondering when.

"We have a similar active fault offshore, so we will someday experience an earthquake and tsunami similar to the one that just hit Southeast Asia," said James Roddy, community education coordinator for the Oregon Department of Geology and Mineral Industries, in a statement.

State and local agencies have spent the past decade developing warning systems, evacuation plans and safety regulations to prepare coastal communities for the possibility of a devastating tsunami.

In 1995, the Oregon Legislature passed a bill requiring the state to map specific areas that could likely be inundated by tsunamis.

Certain types of facilities — such as schools, hospitals, fire stations and police stations — are now prohibited from being built within these areas, known as potential inundation zones.

The bill also requires schools located within the potential inundation zones to teach students in kindergarten through eighth grade about tsunamis and evacuation.

An active fault — or seam between two of the tectonic plates that comprise the earth's crust — sits just miles from the Oregon coast.

This area, known as the "Cascadia subduction zone" is almost identical in size and activity to the one the area that moved under the Indian Ocean last week, generating a massive earthquake and launching deadly tsunamis.

The last time the zone produced a major earthquake was on Jan. 26, 1700. Scientists have used geological and biological data to deduce that the earthquake was of the same magnitude as the one that hit Southeast Asia this week.

There are actually two types of tsunamis that can cause damage to Oregon — local and distant.

The most destructive type of tsunami would be generated locally, by an earthquake in the Cascadia subduction zone.

In that case, "the earthquake itself might last up to four minutes, damaging roads, bridges and other facilities," said George Priest, a state coastal geologist, in a statement.

"Within 10 to 30 minutes after the start of the earthquake, the first of several large tsunami waves will strike the coast," he said. "People must realize that strong shaking at the coast means it is vital to evacuate immediately inland or to high ground. That is our challenge — to create a culture of tsunami awareness before this event can happen."

Jay Wilson, earthquake and tsunami program coordinator with Oregon Emergency Management, said a strong earthquake may be the only warning of an incoming wave.

Wilson urged residents and visitors to learn the tsunami evacuation routes for their coastal communities. Some evacuation routes are clearly marked with street signs, but signs in some areas are not yet posted.

"During a tsunami evacuation, do not linger or return to the beach to watch for the tsunami," Wilson said. "An approaching tsunami travels at jet speeds in the open ocean and cannot be outrun when making a landfall. Wait for the ‘all clear' (signal) from local officials before returning."

Local authorities are responsible for informing people when a threat has passed and the situation is "all clear."

A 1999 study by the Oregon Department of Geology and Mineral Industries estimated the damage that might be caused by an earthquake of magnitude-8.5 — slightly smaller than the one that hit Southeast Asia this week as well as the one that hit the Oregon coast 300 years ago.

According to the study, more than 5,000 people would likely die in the event.

"That's assuming that a few thousand would die from the actual tsunami, and another few thousand would die... from building damage," said Brian Atwater, a geologist for the US Geological Survey.

And the building damages alone would likely cost $12 billion to repair, the study concluded.

A type of tsunami more likely to affect Oregon is a distant tsunami, which is generated by an underwater earthquake anywhere in the Pacific Ocean.

Most distant tsunamis would arrive four hours or more from the time of the earthquake causing them.

The National Oceanographic and Atmospheric Administration monitors a station in the Pacific Ocean that can alert people on the coast to approaching waves, state officials said.

Still, officials said they have more work to do in preparing coastal communities for tsunamis.

A 1998 survey of coastal residents in Oregon showed that many people remain unclear on what causes tsunamis and what to do if they feel a large earthquake at the coast.

"Our warning systems need to work better and people at the coast really need to take the tsunami threat seriously," said Vicki McConnell, a state geologist. "Their lives depend on knowing what to do when a large earthquake and tsunami occur at the coast."

Geologists 20 years ago discovered that the Pacific Northwest coast is prone to huge earthquakes, which launch tidal waves known as tsunamis. At least 17 major earthquakes have happened in the area in the past 10,000 years.

And scientists aren't sure when, but they believe another earthquake will someday rock the Oregon shoreline.

"The bad news is that it would be a horrible event," Roddy said. "The good news for Oregon and the Pacific Northwest is that we are much better prepared than the countries around the Indian Ocean to respond to an event like this."

More information about tsunamis and the Oregon coast is available at www.oregongeology.com.

_

[Servant of Eru]

Heheheh, knew about all these already. My teacher in 7th grade was a sort of amateur seismologist.

Lucky for me, I'm in the mountains, where we really have no natural disasters. I shall be high and dry in the event of an extra-terrestial, or any other type of tsunami. Closest seismological landmark to me is Mount Shasta...might sprinkle me with ash if it blew, but not much else.

[LANMaster]

Interesting possibility, Paul.

Thanks for posting the story.

[angelize56]

Doomsdayers!

Could It Happen Here? You Bet

A tsunami striking the U.S. is not a question of if but when

By J. MADELEINE NASH

Posted Sunday, January 2, 2005

Nothing even approaching last week's toll of death and destruction has ever visited U.S. shores, but that doesn't mean North America isn't vulnerable. Large tsunamis are not that rare, especially in the Pacific, and every now and again, they crash into familiar ports of call, sweeping away people and property. In 1960, for example, a tremendous earthquake in Chile unleashed an armada of giant waves that killed 61 people on the island of Hawaii and then moved on to kill at least 100 more on Japan's Honshu Island. Four years later, a tsunami triggered by an earthquake off the coast of Alaska resulted in more than 100 deaths in Alaska, four in Oregon and 13 in California, plus $100 million in property damage along the western coasts of the U.S. and Canada.

And those are just the tsunamis in recent memory. The prehistoric record is more disquieting. Geologist Brian Atwater of the U.S. Geological Survey has assembled compelling evidence that as recently as 300 years ago, huge tsunamis of shocking power pummeled the Pacific Northwest, from California to British Columbia, reshaping coastlines and surging far up rivers and streams. The culprit: an undersea fault in the Cascadia subduction zone that bears more than a passing resemblance to the fault that just ruptured off Sumatra. "There are so many similarities between what happened there and what could happen here," says Vasily Titov, a tsunami modeler with the National Oceanic and Atmospheric Administration in Seattle. "It's not a question of if but when."

The more scientists look into the tsunami threat to North America, in fact, the larger it seems to loom. Hawaii not only sits in the path of tsunamis that are generated around the Pacific—in 1946, a wave unleashed by a temblor off the Aleutians killed some 170 people in the city of Hilo—but it also harbors its own, homegrown threat. Tsunamis can be triggered by massive landslides as well as earthquakes, and University of Hawaii oceanographer Gary McMurtry has evidence to suggest that about 120,000 years ago, a landslide unleashed by the Mauna Loa volcano created a mega-tsunami that heaved sand and sea fossils 1,600 ft. up the slopes of nearby Kohala.

The U.S. tsunami danger is not confined to the Pacific's hyperactive Ring of Fire. In the Canary Islands, the western slope of the Cumbre Vieja volcano poses a threat to Atlantic coastlines. Should it collapse all of a piece, a scientist from University College London warned last week, the big splash would send tsunamis coursing through the Atlantic at hundreds of miles an hour. According to one nightmare scenario, cities up and down the East Coast would be swamped by waves as tall as five-story buildings.

Fortunately, tsunamis take time to travel, which can give populations in harm's way anywhere from a few minutes to many hours to flee. For this reason, 26 countries have banded together to establish a tsunami-warning system for the Pacific (though not for the Atlantic Ocean or, alas, the tsunami-ravaged Indian Ocean). As presently configured, it's far from perfect, producing a 75% rate of false alarms. But that should change with the deployment of a new generation of detectors that can be positioned deep underwater, away from surface chop. In November 2003, a trial run of the system determined that a tsunami unleashed by an Alaskan earthquake would be too small to do any damage when it reached Hawaii, thereby avoiding an unnecessary and costly coastal evacuation like the one caused by a false alarm eight years earlier. After last week's disaster, however, few are likely to ignore the tsunami sirens the next time they sound.

[LANMaster]

I remember a couple of times that the West coast was issued tsunami warnings.
Ignorant as I was at the time, I thought that was the best time to wax up the board and hit the surf waiting for an easy big wave to catch.

Thankfully nothing noticable came ashore. It might have washed me miles out to sea without even giving me a big wave to surf.

The West coast tectonic plate is such that a major shift might cause San Francisco Bay some damage, but not much more along the West coast. The fault line is too close to the shore to allow a tsunami to build into a massive surge.

[plschwartz]

Originally Posted by LANMaster

Interesting possibility, Paul.

Thanks for posting the story.

One of the reasons I posted this is because this is a danger we can do something about.
We can level the whole thing or at least as much as needs be done. It is a large job but do-able In the Hong Kong airport project 340mil cu meters were leveled and placed in two years. I realize this is much bigger but there would be little need to move material as it would all fall down into the sea. Perhaps this rock could be used to slow down the possible slppage of the block to avaoid a tsunami.
Anyway if we measure possible danger in Saddams (either Saddam (theoretical) or Saddam (actual) and the cost we have a baseline of dollars/Saddam in which to gauge cost/benefit analyses.
I suggest that removing this possible threat is well worth it.

[LANMaster]

I find it interesting that you would take that approach.
What about the indigenous species there? What about the destruction you'd be causing to the Earth?

I think early warning is the key rather than moving a mountain which may, or may not prevent a slide.
As far as the terrorist threat to cause netural-ish disasters, we may as well plug up Niagra Falls because someone might blow it up.

Naah, I say leave the Canary Islands alone and place warning sensors around the ares. A tsunami from there would take 8 hours to reach the East Coast of the US anyway. Plenty of time to evac. for a tidal surge.

[plschwartz]

Originally Posted by LANMaster

I find it interesting that you would take that approach.
What about the indigenous species there? What about the destruction you'd be causing to the Earth?

I think early warning is the key rather than moving a mountain which may, or may not prevent a slide.
As far as the terrorist threat to cause netural-ish disasters, we may as well plug up Niagra Falls because someone might blow it up.

Naah, I say leave the Canary Islands alone and place warning sensors around the ares. A tsunami from there would take 8 hours to reach the East Coast of the US anyway. Plenty of time to evac. for a tidal surge.

I think that 8 hours for evacuation of Fla is impossible. They are talking of a wave that might cross Fla! Same for Long Island with 4mil people and two roads out. Some of the bays and rivers on east coast are natural tsunami conduits. And Carribbean and Gulf coast??

BTW I was talking of natural disasters. I am much less afraid of terrorists. Compare ourlosses with those of Asia. We did make a mountain out of a molehill about 9/11 in the grand scheme of things. I will not go into why.