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Congratulations. You actually can form a complete (if unsubstantiated and erroneous) argument. I stand corrected.

In case you forgot, this all began with your unsolicited post to me, after I informed another FREEPER that the TV docudrama program in question was likely to be on the Discovery cable channel, which boiled down to this bit:

This is absolute hogwash, according to all but a handful of geologists. The "Tsunami Society" was very critical of such claims.

Well, the "Tsunami Society" is not a recognized purveyor of "TRUTH" in this field and a mention of (not even a link) to a (very unprofessional) web site does not constitute citing evidence to back up your bald claim that "this is hogwash." And the evidence I have come across in a very simple search of bona fide UNIVERSITY and RECOGNIZED PROFESSIONAL RESEARCH CONFERENCES clearly makes your claim false, on it's face, that "all but a handful of geologists" disagree with this theory. It is still an open question. Your claim is bogus.

And to your little challenge at the end of your post:

Please state what YOU actually believe and discuss the details rather than just say that there are people who believe both ways.

Fine, here you go:

I believe that it is likely that large volcanic island collapse events can cause catastrophic tsunamis, almost certainly far more devastating than the Indonesia tsunami of 2005 and that the overwhelming, though not conclusive, evidence supports that position. More importantly, I believe that irrelevant attempts to dismiss such speculation as "hogwash" are not only ill advised, they are clearly silly and, in fact, dangerous.

I mentioned this before, but it is all to similar to the dismissive attitude of the folks that ignored concerns about launching the Shuttle Challenger when temperatures were below freezing.

Have you ever heard the phrase "this is away from goodness?" You say you are "quite capable of googling." Fine. Do a Google search on that phrase and learn something about both Murphy and Finagle. Do you even know who Murphy is? If you are, as you say, an engineer, you shouldn't need to look that up. If you are an engineer I would be very afraid of partaking of any structure or design that you were involved with based on your attitude expressed in this exchange.

Ignoring, as you have, the arguments of professionals in the field in a dismissive way about concerns raised over a serious question is a really bad thing to do. Doing so with no more "evidence" than a vague mention of an amateur "society" that supports your claim is ludicrous.

Is it proven? No. Did a TV channel hype the presentation? Yep. Does that have anything to do with whether or not the question raised is of concern or the conclusion reached is correct? Not a chance.

Have you ever heard of "peer review?"

Again, rather than discuss the issues calmly, you seem to only be able to react angrily to scrutiny of the theories of Simon and Ward. I have not once made a personal comment about your ability to reason. Yet you cannot refrain, apparenly from doing likewise. But I raised very common sense issues regarding the comparison of the Indian Ocean and the Day/Ward theories of Cumbre Vieja, and you refused to address even one. All you come back with is harsh criticism to even question this theory unless I wore the title of geophysicist or hydrodynamicist. I have gone back and re-read Simon Day's paper on the La Palma possibility, and I am no more impressed with his thesis. I followed your suggestion and researched the Hawaii 2003 conference. Everything points back to Simon and Ward. As far as I can tell, they are the main proponents for the La Palma mega-tsunami and the magnitude suggested. I have not yet found experts who sign on to the magnitude of the effects predicted by Simond and Ward. Please point me to some. I searched on Gillis and did not find him specifically commenting on La Palma.

I have not disputed the chance that landslide-based tsunamis have occurred in the geologic past. That is both hard to prove or disprove. My comments have always been directed at Day and his La Palma theory, particularly the magnitude of the effects he predicts.

Have you read Day's thesis? Can we discuss the issues without name calling? What do you think about his prediction that the slide would be 100 m/s into the sea? He describes a sub-marine slide that slides from sea-level to sea-floor 4000 meters deep over a distance of 60km. Now, I don't know how linear the slope is, but that is an average grade of only about 6.5 degrees. He assumes nearly no basal friction (calls it a pressurized mud cushion). I find it hard to believe that, even in the absence of basal friction, that gravity (the prime cause of the slide) would cause such a fast slide across a mere 6.5 degree grade. He generally chooses worst-case scenarios (500 km^3 volume, 100 m/s, and the assumption that the slide will be one big block).

I also have a problem with his wave-propagation simulation technique. While his mathematical model appears very complicated, it is likely (my opinion... blast away) that it is in reality woefully inadequate, with way too much uncertainty built into it. The model is a function of both time and the radial distance away from the landslide. The problem I have with this simulation is:

1) Any error inherent in his model would be magnified/multiplied the further in time and also in radius.So while it may be accurate within the first few km's, the error across the ocean would likely be so large as to be useless.
2) There is no practical way to measure the validity of the simulation. You can test it on small scale models (little aquariums, etc) but there really is no practical way calibrate his model/simulation as there has not been volcanic collapses to test the model on. I'm familiar with the Lituya Bay slide in Alaska, but that took place in what was essentially a big bowl, not really similar to large-distance wave propagations due to landslides.
3) His model appears to be one that merely predicts amplitudinal waves... not the type that are normally associated with long-distance tsunami propagations. My problem with this is that the strength of most tsunamis I am aware of comes from transverse wave... pressure waves... where the wave amplitude above sea-level (the basis for Day's model) is not the important factor. Wave amplitudes above sea level dampen relatively quickly, and do not have the propagation efficiency of transverse waves. An amplitudinal wave can propagate, but not be devastating because it is largely local up and down circles near the surface of the water. They can produce a fairly large crash on a beach, but the water does not continue to surge onto the beach like a tsunami. His model is basically a standing wave model that propagates radially. I don't think it allows for additive or subtractive interference with existing wind-based ocean swells.

Believe it or not, I am really open to you changing my opinion. I have examined critically Day's theory and find it highly speculative, and somewhat sensational. I wish you would address the issues I have raised rather than insult me and tell me I haven't the aptitude to question these theories or to tell me to Google. If you have specific instances of experts backing this theory, please, by all means show me a link.

Also, rather than just blithely labeling the Tsunami Society as an amateur group, please back up your charges with real sources.