Talk:Megatsunami

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A section of the article was altered to state that a megatsunami from the island of Las Palmas 'would' destroy U.S. east coast cities and gave specific dates as estimations; this was deleted for lack of credible source information and as it appeared to likely be an attempt at sensation rather than fact.

This article needs some work, as it's remarkably vague (Who were the two geologists? When did they "observe evidence of unusually large waves"? Where is the "nearby bay"? Nearby in relation to what? Is it Lituya Bay?) and possibly states facts incorrectly. Unfortunately, I need to do some research before I touch the article further. --Goblin 01:17, Jul 6, 2004 (UTC)

Also, if I'm reading this correctly, one paragraph says that the last megatsunami happened 4,000 years ago, and the next paragraph says that there was one in 1958. Either this is inconsistent, or stated confusingly enough as to sound inconsistent to me.

Contents 1 Article OK 2 Terrorist Threat of Trigging MegaTsunami 2.1 Math 2.2 15-25 meters? 3 Why does this article exist? 3.1 NPOV Query 4 terrorists 4.1 Prevention possibilities 5 La Palma research (grammar) 6 Definition 7 Megatsunami vs tsunami 8 Image added is not of Megatsunami but Tsunami 9 Chicxulub Megatsunami

[edit] Article OK

Not confusing to me. the article was referring to the last time a megatsunami was s big it took out the coasts of an entire continent. "Some are so large that they can devastate the coasts of entire continents. The last such event (that we know of) occurred approximately 4,000 years ago".

Good article.

Claudius

[edit] Terrorist Threat of Trigging MegaTsunami

I posted comments regarding the possibility of terorists triggering megatsunami events at locations such as La Palma. They were promptly deleted within minutes. I believe the comments are relevant to the page on megatsunami's and on the La Palma page as well. What does it take to have this concern added to the page such that people won't arbritirally delete it? The comments are not meant to be a discussion but to be ask the serious questions about this very real concern. Anyone reading the megatsunami or La Palma pages NEEDS to be aware of this potential threat that they pose and with all the publicity caused by the very sad 2004 tsunami in Asia it's an important opportunity to get the message out to people, who hopfully will ask their government representatives about it. What would an appropriate paragraph about this be? Also were can I find my deleted comments? - peter

I propose the following be added to the megatsunami page or to another page about this important topic:

Megatsunami Terroist Threat It is possible that terroists could trigger a megatsunami event, at locatations such as La Palma, and cause wide spread global destruction. This is a serious threat that needs to be addressed by all governments and concerned citizens. What can you do to ensure that your government is taking actions to prevent such actions and protect these sensitve geological locations?

The above comments aren't written in an encyclopedic style. The Encyclopedia Brittanica for instance, would never say "What can you do to..." Remember that Wikipedia is an encyclopedia.

I suggest you'd be better off writing to your Congressperson or to the Department of Homeland Security if you think it's warranted. -- Curps 09:26, 29 Dec 2004 (UTC)

Thank you for your comments. How about we work to rewrite this topic into encyclopedia style? Any suggestions? There must be a way to include comments designed to have people act on important events even in encyclopedia style? The point isn't that I write to my government representative, the point is to raise the importance of this issue in the entry such that people clearly understand that it's a serious concern. Surely that can be written in an encyclopedic style? The point is to inform the many people reading the page about the nature of the danger. They are the ones who can choose to act or not. Leverage of people power for the betterment of mankind and the planet is what Wikipedia is about, is it not? -- peter

At the end of the paragraph that says:

The aftermath would hold obvious implications for affected populations, governments, and for the global economy. While potentially not as devastating as a supervolcano, a megatsunami would be an unprecedented disaster in whatever region of the world it occurred.

you could add something like "Some even suggest the possibility of this scenario being triggered deliberately by terrorism."

However, I personally don't think terrorism is that much of a threat. A big explosion would produce many small chunks hitting the ocean, and not one big chunk. The multiple small chunks wouldn't trigger a megatsunami. Getting a single big chunk to slide into the ocean would probably be a matter of chance and luck, something Mother Nature might do once in a very long time, but not the typical landslide. -- Curps 09:35, 29 Dec 2004 (UTC)

Your suggestion is a good way to include a taste of the terrorist threat discussion. If you saw the BBC documentary "Mega-tsunami: Wave of Destruction" (http://www.bbc.co.uk/science/horizon/2000/mega_tsunami.shtml) about La Palma and how unstable the rock there really is you'd understand that it's a real possibility for expert explosives experts to trigger. I'm not the one making up this threat. Here is a link http://www.benfieldhrc.org/SiteRoot/in_the_news/press_cuttings/Insurance%20Day/new_york_tsunami.htm to an article about it and a quote: "Scientists at the Benfield Hazard Research Centre believe the catastrophe will be triggered by volcanic activity in the Canary Islands (La Palma)." -- PeterWLount

Well, if you like, go ahead and add that sentence that I suggested. -- Curps 09:53, 29 Dec 2004 (UTC)

thanks for your suggested sentence. I've added it in and it's a good start. What about linking to the BBC documentary page that I reference in my above comment? PeterWLount

I think someone already added it earlier, under the "External links" section. -- Curps 10:02, 29 Dec 2004 (UTC)

Yes, that is the same link. I do think that the issue needs to be highlighted stronger. As we can see from recent events in Asia and NYC the treat needs to be taken seriously. Peterwlount 10:09, 29 Dec 2004 (UTC)

Yes. The natural threat is serious enough, even without a possible terrorist threat. But for various reasons, I think terrorists would have a difficult time to pull it off... too much conventional explosive would be required and it would have to be detonated deep underground instead of at the surface. But at least Homeland Security should take the natural threat seriously. -- Curps 10:16, 29 Dec 2004 (UTC)

The point is that it's likey much easier for terroists to cause a La Palma megatsunami event than to obtain and explode a nuclear bomb in North America. Also La Palma would likely cause more devestation than a single nuke. Discounting the possibility without a proper scientific analysis isn't advisable. The reason that La Palma is a problem is it's specific brittle rock formations that are fragile and sensitive to disturbance. It could take a lot less less well placed (pun intended) explosives than one would think to let loose these rock formations. The documentary is a must see. Peterwlount 10:22, 29 Dec 2004 (UTC)

I think one of the articles linked to at Cumbre Vieja (the third BBC article) mentions that the megatsunami only happens if a single entire block of rock slides into the ocean in one piece. If it's broken up into ten smaller pieces, there won't be a megatsunami. That's why even if the terrorists were able to cause a massive explosion, it would probably be beyond them to cause one single block of rock to slide into the ocean rather than a million smaller boulders.

Anyways, I'm going to call it a night. Good talking to you. -- Curps 10:26, 29 Dec 2004 (UTC)

Yes, and to you a peacefull and prosperous new year.Peterwlount 10:27, 29 Dec 2004 (UTC)

Someone keeps removing the addition without any explaination. Sigh. Peterwlount 01:32, 30 Dec 2004 (UTC)

I deleted it because it is really silly. The amount of energy required is of the order of a volcanic eruption or large earthquake, which is in the range of large nuclear weapons and impossible to achieve with conventional explosives. Such a nuclear explosion would have to be set off deep underground under the ocean and this major engineering feat would have to be accomplished without detection. We are all entitled to our paranoid fantasies but this one goes too far and spoils an otherwise good article. --Zero 10:57, 30 Dec 2004 (UTC)

Very silly indeed. The much smaller landslide caused by the 1980 eruption of Mount St. Helens (still the largest in recorded history) was set off by an eruption that released an amount energy equal to 20,000 Hiroshima-sized atomic bombs. If a terrorist had that many atomic bombs, I'm certain they would find other uses for them other than creating the possibility of causing a tsunami-inducing landslide. However, human activity can influence volcanic activity. So it is theoretically possible that something less - perhaps much less - than 20,000 atomic weapons could cause the collapse if the volcano is close to erupting anyway. One could then, and only then, be able to push things in a desired direction with relatively a small amount of force. --mav 05:52, 31 Dec 2004 (UTC)

Just because you think it's "silly" doesn't negate the possibility. Mount St Hellens wasn't as unstable as La Palma. Let me reiterate the following: If you see the BBC documentary "Mega-tsunami: Wave of Destruction" (http://www.bbc.co.uk/science/horizon/2000/mega_tsunami.shtml) about La Palma and how unstable the rock there really is you'd understand that it's a real possibility for expert explosives experts to trigger. I'm not the one making up this threat. It's not a stretch to imagine humans studying this highly unstable geology in detail and using specific controlled demolishion of high explosives, just like taking down a sports statium, to bust open the "natural dams" holding up the massive quantities of water inside La Palma. It's the water inside La Palma that's the threat since it's the sustpected cause of the 16 meter slip of a 2km section of the mountain side that occured the last time the island erupted. In addition, the point about responsible warnings is that they are to get people thinking about the possible reality of something. If you keep deleting a warning you are supressing an appropriate and important form of communication and preventing people from having the chance to think about the threat. Most likely due to the repeated deletions a new page is needed to counter your inappropriate deletions. If you have an alternative version to introduce please do so. I'm not interested in an add/delete war, I'm interested in an appropriate article to document the potential of this weapon embodied in La Palma and other unstable megatsunami locations. -- PeterWLount

That article you cite says nothing about any terrorist threat. If you want your "theory" to gain traction Wikipedia is not the place since WE ARE NOT A PRIMARY SOURCE. Try to get your idea published in the the scientific literature first and then come back to cite it here. See Wikipedia:What Wikipedia is not #s 8 (Personal essays), 9 (Primary research), 16 (News reports) --mav 17:03, 31 Dec 2004 (UTC)

I've added the following to include the disenting voice of the "deleters": "While some are skeptical of the probability a few suggest the possibility of this scenario being triggered deliberately by terrorism using controlled demolition to affect La Palma's unstable geology." -- PeterWLount

Not good enough. Why not add the possibility of megatsunamis being created by aliens or by malicious demons? That's about as credible. Show us a qualified person (someone with scientific authority to speak about massive earth movements) who thinks this "threat" is credible. Btw, the BBC show does not make any claim about terrorist threats. It is a crackpot idea and no more than that. --Zero 15:38, 31 Dec 2004 (UTC)

I would like to add that it _could_ be triggered by large scale demolition work, but this does not have mean malisicious intent, a goverment may decide to demolish pieces off of it in order to cut down on the mass of land that will utlimately create the tsunami when it plunges into the ocean. But any such operation would not go unnoticed and therefor any terrorist threats are moot --Jimius 15:48, 31 Dec 2004 (UTC)

[edit] Math

The point is that it's likey much easier for terroists to cause a La Palma megatsunami event than to obtain and explode a nuclear bomb in North America.

I don't know about that, I think it would take some math for that, a lot of math to correctly detonate the correct explosives with the right strength at the right times at the right places. And Zero0000 is right as well, the explosives would need to be detonated deep underground, and we're talking about 5.5 trillion tons (I'm not talking about tonnes) of earth that will be causing this megatsunami.

I agree with the anonymous person who wrote the above. It would be very easy to detonate a nuclear explosion in North America. Only 12 kilograms of plutonium is sufficient to cause a self-sustaining fission reaction; that amount could be carried in a briefcase. The same can't be said for La Palma; it would take a lot of work, as well as substantial geological knowledge, large-scale drilling crews and lots of time. It cannot be done. thefamouseccles 13:53, 1 Feb 2005 (UTC)

[edit] 15-25 meters?

What source said something about 15-25 meters? I found several that said 90 meters (295 ft). --Mac Davis 10:51, 1 Jan 2005 (UTC)

I Found several that said something like 150 to 500 meters.Wiki236

[edit] Why does this article exist?

Nowhere in science is a 'megatsunami' ever referred to. There's certainly no scientific defintion. It's purely a pop-culture term. Dan100 19:57, Jan 4, 2005 (UTC)

I have heavily edited the article to reflect this, and corrected many of the fallacies previously in the article. Dan100 20:12, Jan 4, 2005 (UTC)

While I make no claim that it's the perfect source, it has been used on at least two Discovery Channel documentaries by geologists during interviews, so I think that that justifies the article's existence. You certainly can't call these events normal tsunami. thefamouseccles 13:49, 1 Feb 2005 (UTC)

This article should simply state: Megatsunami is a non-scientific term sometimes used to mean a very large tsunami. or else be removed altogether (linking the search term to tsunami).

Motivation: A tsunami can by definition be caused by any seismic event, including land slides, submarine slides, earthquakes, submarine volcanic eruptions, meteorite impact, and so on. It is completely un-scientific to separate the two. The fact that geologists use the term in a TV program is equivalent to them saying "it was a very very large tsunami", since mega is a prefix used to signify something very large. Well, this is my POV as someone who has worked with classifying natural disasters.--Lindorm 21:05, 19 July 2006 (UTC)

[edit] NPOV Query

"In modern times, this phenomenon would be made even more likely to occur based upon President George W. Bush's adherence to scripture and disregard of the Kyoto Accords. The sinking of the polar ice caps is likely to follow the abandoment of such environmental accords and create large scale destruction from these giant waves."

This doesn't seem to be a particularly neutral point of view.

--Staz 21:36, 4 Jan 2005 (UTC)

It's also a load of rubbish. Dan100 20:14, Jan 6, 2005 (UTC)

[edit] terrorists

I fully agree with the danger of that terrorists can take advantage of such environmental desasters, what i donot understand is why the collaps of la palma cannot be stopped. I suggest that America should pay every dollar in investigating this problem instead of sending the money to Mars. I'm not a scientist, i think you noticed that,but there seems to be water in the mountain of la palma, that will cause the collapse, maybe they should get this out, again you see i'm not a scientist, but maybe if you put 50 scientists on this problem for 10 years you have a solution and after that we can go to Mars. Why wait for this to happen its stupid. The same with prevention of a hit from a meteor from outer space, because it happens only once in 100.000 years, they put it in nuclear bombs. A meteor is a 1000 nuclear bombs at once!

by dmx from Holland

It takes more than a bit of scaffolding to hold a 5-trillion-ton mountain in place, and any drilling, building or mining that's substantial enough to make a difference might very well be substantial enough to trigger the landslide itself. What we need to do is stop trying to prevent landslides and tsunami and volcanic eruptions, and start understanding what we can do to prevent human death from the effects of these disasters. Early warning systems, for instance. It'd make a lot more economic and environmental sense, plus it's just common sense: to take your meteorite example, how will we stop a chunk of solid rock - sometimes even iron - moving at nearly 40,000 kilometres an hour? And I think that the idea of terrorists causing a landslide like this is just paranoia; I agree with Zero on that. People are too afraid of terrorists; if we fear them, they've already won. thefamouseccles 13:38, 1 Feb 2005 (UTC)

[edit] Prevention possibilities

This is technically original research. If it's feasible, I think it's important enough to put in a place like this (the talk page).

3 potential ideas (though I currently have insufficient understanding of physics to know whether they are feasible).

1) Wrap Volcanic landslide prone areas such as that near the Cumbre Vieja volcano on La Palma in sufficient density of carbon nanofiber composites to prevent collapse. Have sufficient slack in the wrap for minor movement to occur (such as is normal in volcanic expansion of land) without causing the nanofiber wrap to break, but sufficient taughtness that it can prevent a potential tsunami causing collapse. Said wrap can be sub-surface (against the rock), thus allowing normal vegetation and animal life above it.

2) Quarry the gigatons of rock out. Do so in a way that would prevent the quarrying to unintentionally cause the very collapse it is trying to prevent.

2)A) Do number 2 after you have done number 1. This will help prevent potential collapses while quarrying. It's possible other support mechanisms are strong enough to support the teratons of mass (especially as the mass is already partly supported by the island it's a part of.

If a tsunami occurs: 3) Vertically or angled deployable/telescoping breakwaters on the continental shelf. These can be deployed if a tsunami early-warning signal goes off. They would cause the low-level tsunami waves to (at least partially) prematurely crest in the ocean by giving them a false rise to crest against. It's possible the breakwaters couldn't fully withstand the sheer power of the tsunami wave front and would consequently be destroyed while only mitigating some of the tsunami's power, but this is probably preferable to having the full impact of the wave hit mainland. If more than one layer of breakwaters exist, this might result in a significant decrease of tsunami force against the mainland (where a mainland can be an island or continent). 24.22.227.53 15:38, 2 September 2005 (UTC)

[edit] La Palma research (grammar)

"the source of the next large-scale megatsunami is the island of La Palma, in the Canary Islands, ~although further research has dismissed the threat. However,~ recent research has found that a large section of the island will break off into the ocean, causing a megatsunami"

I don't know of what research this paragraph refers to, but as it stands the wording is somewhat contradicatory and more than a little ugly. So I'm going to cut out the text denoted by tildes, and hope that someone out there with more knowledge on the topic can clarify or re-write. - Whoops sorry I forgot my signature --Tocqueville 17:08, 30 July 2005 (UTC)

[edit] Definition

The first paragraph contains two comments regarding the definition of a megatsunami, which seem to contradict each other.

1. "A megatsunami is a form of displacement wave, related to tsunamis in name only."
2. "the term generally refers to tsunamis with waves from 40 metres (131 feet) to over 100 metres (328 feet) tall."

The first seems to indicate that a megatsunami is not a type of tsunami, the second indicates that a megatsunami is a type tsunami. Can anybody clarify this, please? Cheers TigerShark 15:41, 4 September 2005 (UTC)

Whups, true !! Will do ! FT2 08:25, September 8, 2005 (UTC)

[edit] Megatsunami vs tsunami

I'm quite confused as to the difference between a megatsunami and tsunami. The article doesn't explain it very well. AFAIK, a tsunami can be caused by any number of things, meteors, landslips, seismic activity, volcanos etc. This article appear to suggest megatsunamis are caused by landslip and meteors whereas tsunamis are caused by seismic activities which I'm pretty sure isn't true. Seismic activity is AFAIK the most common cause for tsunamics, probably because it's rare for landslips not caused by seismic activity to be of sufficient size and power to cause a tsunami of any significance and meteors are very uncommon. Of course they do occur, the Vajont Dam disaster was a tsunami and anyone who suggests it's not is incorrect. However Tsunamis are normally not localised but AFAIK they can be localised, it simply depends on the body of water involved and the event causing the tsunami. Megatsunamis is defined as being 'bigger' then the average tsunami but there is no limit to the size of a tsunami, it simply depends on the size and power of what cause the tsunami. So really I can't see any difference between a megatsunami and a tsunami as this article appears to suggest.

Then the article hasn't been written properly. A megatsunami occurs when there is a large displacement of water because of a mountainside or ice falling into it, and typically occurs in a closed channel, i.e. a fjord or other steep, narrow bay; if such a slide or debris-fall or ice-collapse occurs in constrainted waters, the wave can be over a mile high, although it dissipates rapidly after it leaves the fjord. A regular tsunami is rarely more than 30m in height and is not caused by displacement, but by subsidence/shockwave compressions within the body of water. Skookum1 08:03, 8 February 2006 (UTC)

From the current description, it appears to me that this non-scientific term is simply referring to a special case tsunami, specifically a very large tsunami,

It is not a non-scientific term - a rare Greek-Japanese hybrid form - and was coined by the geologists/geographers or whatever they were who charted the aftermath of the Lituya Bay incident).Skookum1 08:03, 8 February 2006 (UTC)

possibly localised and given the size most likely not cause by seismic activity (although I suspect most people who use the term will call a very large tsunami caused by seismic activity a megatsunami). If I am correct, it's probably best to correct the article to clarify that a megatsunami is simply a losely defined term used primarily by the media, to describe a tsunami of a particularly large size and destructive power, most likely not the result of seismic activity. Or something along that line... Personally, if my understanding is correct, I thing the megatsunami is a rather stupid term. Nil Einne 11:11, 8 January 2006 (UTC)

IMHO, having worked with classifying natural disasters for a government where tsunamis are a threat, this page should ideally be removed (or else it should be a page on popular misconceptions, not natural disasters). It is simply a question of magnitude, not a different phenomenon. --Lindorm

I agree with Lindorm. How does one post an official alert(?) that this article would be merged into tsunami?
One doesn't need to be a geologist to quickly find out that this article and the tsunami article contradict. Among the most jarring phrases was: "Megatsunamis are related to tsunamis in name only: they do not usually have the same cause or appearance." However if you'd go to the tsunami page, you will find out that tsunamis include all the causes of "megatsunamis." Furthermore (as pointed out by TigerShark), parts of the article DO refer to megatsunamis as tsunamis. I didn't see FT2's corrections. The issue seems frivolous even on the semantic level... megatsunami.
I clarified several ambigious phrasings, and edited out a couple of paragraphs in the beginning, I believe the article lives much better in accordance with the tsunami article. --Binba 07:11, 14 November 2006 (UTC)

[edit] Image added is not of Megatsunami but Tsunami

I took the image entry out; it should be on the tsunami page. A megatsunami is caused by landslips falling into the ocean, not landslips beneath the ocean. An illustration for this article would best be of Lituya Bay or whichever it was in Alaska which had the 5000'er back in the 1950s; there's images of the debris path, i.e. the wiped-out trees up to the elevation of the wave.Skookum1 08:03, 8 February 2006 (UTC)

[edit] Chicxulub Megatsunami

Anyone have any info about how high the waves were after the comet that killed the dinosaurs hit?--Threedots dead 22:50, 4 March 2007 (UTC)