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tsunami, original a japanese word, is now the standard term for what used to be called a tidal wave. since tsunami are not generated by tidal forces, and since tsumani means 'great wave' it is a more acurate term.
we have discussed some oceographic terms, but in WOW's link over in I & A, the term bore is used.
tidal bores (are there other kinds?) are well known.
if a river bed has a drop in it.. (a substanstial drop, but not one that causes a water fall.)
________****____water level of river (*=a surface disturbence)
-------_________(river bed)
AND this change in river bed level is close enough to the mouth, you can get a tidal bore.
the sudden change in the river bed depth, (and low tide--this might actually present as a small water fall, or rapids)impedes the back flow of (upstream flow)the tide. as the tide comes in, it fills the river bed right up to change in depth, and as it 'tops' over the step, there is a surge of tidal water..this surge of water is a tidal bore--one of the reasons for a bore is how water volume moves during a tidal flow.
the best known bore in North America is on one of the rivers that feeds the bay of fundy..(which is known for its extreme tides)
tidal movement of water is very interesting.
tides water moves by 'the rule of 12'
in the six hours or so it takes for a tide to 'change' the water moves in 1/12ths..
in the 1st hour, 1/12ths of the volume of water is moved
in the 2nd hour, 2/12ths of the volume of water is moved.
in the 3rd hour, 3 /12ths of the volume of water is moved.
in the 4th hour, 3/12ths of the volume of water is moved.
in the 5th hour, 2/12ths of the volume of water is moved.
in the 6th hour, 1/12th of the volume of water is moved.
So in the 'middle 2 hours' (1/3 of the time)6/12ths (or 1/2) of the volume of water is moved!
furthermore, in the of the middle two hours, (3.5 to 4.5)--4/12ths (1/4th or 25%) of the water is moved.
i wonder if the tide was high or close to high tide, the effect of a tsunami were much worse, (there would have been more water closer to shore) and if an area was at low tide, its might have mitigated the effects of waves--there wasn't (that i saw) any information about the tides.
in looking at all the images of the 'path' of the tsunami, and the areas that suffered destructions (why were some parts of the eastern coast of india impacted so much more than others?) i wonder what effects the local tides had.
now that i have shared a large percentage of my water knowlege.. perhaps we can explore other specific terms for water (and water movement in rivers, lakes and oceans..)
or is the idea to boring?
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or is the idea to boring?
Fascinating discussion, Of Troy.
Your range is tidal.
I am particularly interested in this:
"So in the 'middle 2 hours'(1/3 of the time) 6/12ths (or 1/2) of the volume of water is moved!"
I can't help but wonder if this 'wave' phenomenon doesn't find expression in other waves including 'waves' in the marketplace where the acceptance of a consumer product, like a cell phone, achieves "critical mass" somewhere, perhaps, in the middle of its trajectory, after the "early adopters" phase, and long before the "market saturation" phase.
Mathematical whizzes are known to have applied "chaos theory" to the stock market successfully.
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In reply to:
and since tsumani means 'great wave'
Merriam-Webster disagrees
Etymology:Japanese, from tsu harbor + nami wave
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Etymology: Japanese, from tsu harbor + nami wave
Well a "harbor" is certainly where the impact of the 'great wave' is felt, Vernon, but I don't think that takes anything away from Of Troy's discussion, do you?
BTW apparently the 'harbor wave' which hit Indonesia was only a meter high* [compared to several times that height elswhere including Thailand] so a tsunami does not have to be a 'great wave' to have great and terrible impact.
* This was reported by the Jakarta Post but it appears to be an understatment because a wave of 2.6 meters was recorded as far away as Mexico.
"Waves of up to 10 meters in height struck Northern Sumatra, the Nicobar and Andaman Islands, Thailand, Shri Lanka, India, the Maldives, Somalia, Kenya and the islands off the African coast. The tsunami was recorded by tide gauge stations not only in the Indian Ocean, but in the Pacific as well. In Manzanillo in Mexico, the tide gauge recorded a wave of 2.6 meters."
http://www.drgeorgepc.com/Tsunami2004Indonesia.html
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Carpal Tunnel
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Vernon! Wonderful to see you again! <grin> Don't think I know you well enough to give you a hug, but...[blowing kiss e].
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I noticed that word bore too, Helen. By "surge" of water, do you mean ...shoot, I can't think of the word I want (no, not bore!)--a sort of backwash effect? That is, when the water hits an obstacle, part of it rises up the face of the obstacle, then curls backwards onto itself? That kind of "bore" would make sense to me: kind of like a whirlpool but horizontal.
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Carpal Tunnel
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When canoeing, I used to call that a stopper wave - great for getting dangerously stuck, for the thrill of it near a sluice for example! I think a bore, like the Severn Bore, is more like a small tidal wave, in that it is a sudden rush of volume moving though the existing water level, no? edit: 'see the movie'! http://www.severn-bore.co.uk/default.htm
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of troy asks: i wonder if the tide was high or close to high tide, the effect of a tsunami were much worse... It was close to a full moon too. I wonder did that have an effect?
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I wonder if the tide was high ... [would] the effect of a tsunami [be] much worse? and It was close to a full moon too. I wonder did that have an effect?Well, at high tide, those on shore would certainly have further to run to escape the wave. Here's a heart-warming story of a family which fled the wave and survived: Family's dog saves boy, 7, from tsunamiToronto Star, January 3, 2004 Extract: "Sangeeta thought she would never see him again. But the family dog saw to it that she did. The dog, called Selvakumar, ducked into the hut after Dinakaran. Nipping and nudging, it did everything in its canine power to get the boy up the hill. "That dog grabbed me by the collar of my shirt," Dinakaran said from under some trees at Pondicherry University, where the family is waiting for relief. "He dragged me out," Dinakaran said.Sangeeta, 24, who like many south Indians only uses one name, had no idea of the drama unfolding below. Once she had crossed the main road to safety she collapsed into tears, screaming over the loss of her eldest son." http://www.thestar.com/NASApp/cs/ContentServer?pagename=thestar/Layout/Article_Type1&call_pageid=971358637177&c=Article&cid=1104707409988How many dogs have saved their owners from peril, I wonder? If only dogs could tell their tales. A dog called Selvakumar and a little boy called Dinakaran.Perhaps this story in yesterday's Toronto Star will inspire someone to send money to Pondicherry University for Dinakaran's education, and imagine, just imagine, what Dinakaran might do for his countrymen some day, or, perhaps, for the world! All thanks to a little dog called Selvakumar. A dog saves a boy from a tidal wave, and turns the tide of history. Now, there's a tale for the Lunar Trail. :)
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