A tsunami video which shows the ocean falling down on the land

(Note: See follow-up entry which explains the wave nature of a tsunami.)

Peter H. writes:

See this horrifying video, one of the most instructive I’ve seen, in which we see some of what you’ve discussed previously (here and here), that the tsunami is not, in any way, a “wave” in the normal sense, but a sudden rise in the level of the entire surrounding sea resulting in the pouring of sea water down into the city, which is now below the level of the sea. Notice how quickly the elevation of the sea level happens. We also see the human element with an adult and child on a rooftop at the beginning and the building completely gone/submerged at the end and the screams of a woman as her house is washed away, presumably with her inside. Finally, just after the sea level has reached its zenith, we just begin to see it recede.

- end of initial entry -

LA to Peter H.

In the video I see the ocean pouring continually onto the land. It’s very strange.

I read Wikipedia the other day on tsunamis, and the article, while not bad, doesn’t help give a true understanding of what a tsunami is, how it is shaped, how it does what it does.

Peter H. replies:

I’m now sort of thinking of tsunamis as rapid, exaggerated tidal surges. Although Wikipedia says the term “tidal wave” is a misnomer and out of favor and, of course, the cause of tsunamis is not “tidal” forces, I think it encapsulates well what appears to be happening here. In addition, Wikipedia shows a series of drawings showing what happens in subduction, when, before the earthquake, the land appears to be raised above its resting position and then is lowered during the earthquake. It may be that not only does the sea rise because of the surge, but that the land is actually lowered. The media have reported that the entire island of Japan changed position because of the earthquake. I suppose it’s possible that the positional change may be not only horizontal but vertical.

LA replies:

But I think at Wikipedia it says that that ocean floor rises up and that this is what lifts the ocean and starts the wave.

I almost feel that we need to do our own home experiments to figure this out. For example, in a large water-filled tank, rig up a movable part of the inside floor of the tank so that it can be suddenly raised, and then see what happens to the water.

Also, presumably a tsunami would radiate outward in all directions from the epicenter.

Also, the Wikipedia article says that the wave length of a tsunami is typically 120 miles. So does that mean 120 miles of raised ocean? But if the whole thing is raised, how can it be a “wave”? Remember that article by someone I posted earlier which said that in a tsunami there is no trough behind the wave. But if there is no trough, how can it be a wave? A wave by definition is a crest and a trough.

March 19

James S. writes:

Here is another video of the tsunami hitting the same port village but taken from a different vantage point.

It includes in its description the name of the village (“Kamaishi in Iwate prefecture”—which CBS was too lazy to do.

And one thing that I’ve been wondering about for the past week: did these towns and villages on the east coast of Honshu not feel the massive earthquake just a moment before? They must have, although I never see any damage already present when the tsunami hit. How much time elapsed? Presumably the heavier the shaking, the closer to the epicenter, the sooner the tsunami arrived?

LA replies:

Yes, we’ve heard very little about the damage done by the earthquake before the wave came.

By the way, I don’t like the word tsunami; it doesn’t work in the English language, particularly when one is using it all the time. I prefer “tidal wave.” Yes, the natural phenomenon under discussion has nothing to do with tides, as Wikipedia points out. But as Wikipedia also acknowledges, tsunami means harbor wave, and a tsunami has nothing to do with harbors.

To me, “tidal wave” is more descriptive.

Posted by Lawrence Auster at March 18, 2011 10:21 AM | Send

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