[ExI] THE END for nuclear power
spike66 at att.net
Fri Mar 25 19:41:05 UTC 2011
On Behalf Of Jeff Davis
Subject: Re: [ExI] THE END for nuclear power
On Thu, Mar 24, 2011 at 5:46 PM, Richard Loosemore <rpwl at lightlink.com>
>> The energy in that tsunami would have demolished any dikes/levies without
so much as pausing for breath.
>.... The tsunami wave travels across deep water with a small amplitude.
Then, when it reaches shallow water near shore, it piles up to its maximum
height, and, as the photos from both Japan and the Indian Ocean tsunami
show, it flows inland. And of course houses and cars and most everything
else is tumbled into flotsam. I do not believe there is much in the way of
a "shock" from the impact. Not at all like the relentless pounding of wave
after wave typical in a hurricane or other maximum intensity ocean storm
making landfall. Rather it seems to be a one time elevated water event of
slightly -- some minutes: 10, 15, 20, ?... Best, Jeff Davis
Jeff, you hit it right on. Even after everything that happened in Japan,
too many people don't understand the nature of wavelength and amplitude.
When they heard of a twenty meter wave travelling 800 km/hr, they imagined a
scaled up version of that monster breaker at the front end of the old Hawaii
5-0 television show. Proles would comment "Too bad Japan was in the way of
that, wouldn't it be cool to be out somewhere on a surfboard and catch that
monster, surf all the way to China, etc."
The Poseiden Adventure movie reinforced the error, with a huge wave
overturning an ocean liner.
But a tsunami isn't shaped like that. A tsunami is more like a pile of
water 20 meters high with 100,000 meters from peak to trough. So the water
level rises over several minutes. The kinds of waves you and I may have
surfed in our misspent youth were more like waves travelling perhaps 30
km/hr, with 50 meters peak to trough. These are two completely different
things. A tsunami going 800 km/hr doesn't have a shock wave. The water can
rise a couple cm per second for ten minutes. This too can cause a hell of a
problem, as we have seen.
If a ship is out to sea, a 20 meter high tsunami can pass underneath at 800
km/hr and the ship would never notice anything amiss. If one is reading a
GPS out there, one can see one's altitude rising for several minutes and
falling for several minutes. But if one were fishing in a quiet sailboat in
deep water on a perfectly windless day, that tsunami would pass right on by
without a whisper.
The destruction on the shore is often from debris being washed first inland,
and then tearing back out to sea with a roaring vengeance.
Any seawall is good. If it is higher than the peak of the tsunami, then
nothing happens. If the water goes over, the seawall still helps but
doesn't solve every problem.
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