Giant Tidal Wave in Thailand.....

Lee Bell wrote:
>>>? >Tidal waves as high as five metres hit Penang and several other
>>>? >Malaysian islands following the 8.9-magnitude earthquake near
>>>? >Indonesia's Sumatra island.
>>>?
>>>? So what's a 5-6m tsunami wave like compared to a regular one? And is
>>>it
>>>? a one shot deal, or does it come in a set?
>>>?
>>>? For one of the largest earthquakes ever, I guess I thought it would be
>>>much bigger.
>>>
>>>Large is relative. A 20' wave still isn't trivial.
>>>
>>
>>To say the least, Alan. I do not know the physics of wave energy, but I
>>remember reading that a 4' wave on one mile of coast generates 35,000 hp
>>of energy. I'm sure that is logarithmic with a 20' wave.
>
>
> Since we know of the deaths and devastation caused by these waves, it's easy
> to say that they are not trivial. On the other hand, we've all seen
> pictures of people surfing on waves of comparable height. It's not clear
> why a Tsunami is so different, but it's apparent that they were.
>
> Lee
>
>
It is probably much like the difference in 80 mph winds and 80 mph winds
in a tornado - the concentration, and speed of the massive wave of
water. Don't know if the wind analogy is very good. Tsunamis are not
just immense in height, but in all dimensions with the element of water
moving at 500 mph.

I am sure in the next several days we will get a much better
understanding of the force.

To all who are concerned about the passengers, crew and staff of Ocean Rover
Dive Cruises. . At the time of the disaster the boat was, and continues to
be, in Myanmar Mergui Archipelago which was unaffected by the tidal waves.

Management is in continuous contact with the boat via satellite phone. The
office and office infrastructure is intact. Communications in Phuket are
very limited at this time. Updates will be posted if necessary.

Diving in Myanmar is good and he boat has been unaffected by the disaster.

John


"KT" <kt_91488044@yahoo.com.hk> wrote in message
news:cqmdg5$qvs2@imsp212.netvigator.com...
> http://www.turkishpress.com/world/ne...8.eimrlc5x.xml
>
> Anyone knows how the situation is at Phuket, Kao Lak & Similan Island?
>
>
>

On Mon, 27 Dec 2004 14:08:41 GMT, "Lee Bell"
<leebell@ix.remove.netcom.com> wrote:

>>> Large is relative. A 20' wave still isn't trivial.
>>>
>> To say the least, Alan. I do not know the physics of wave energy, but I
>> remember reading that a 4' wave on one mile of coast generates 35,000 hp
>> of energy. I'm sure that is logarithmic with a 20' wave.
>
>Since we know of the deaths and devastation caused by these waves, it's easy
>to say that they are not trivial. On the other hand, we've all seen
>pictures of people surfing on waves of comparable height. It's not clear
>why a Tsunami is so different, but it's apparent that they were.

OK.

Normal waves:

------/\---/\---/\----

Go up, down, up, down - individual waves may be (say) 20' from crest
to trough and 50' long from one crest to the next.

Tsunami:

--------- (a mile or more) --------
/ \
-------- -------------

It's not really a 'wave' at all, as we normally think of waves - it's
a huge mass of displaced water. It's much more like the storm surge
beneath the eye of a hurricane, to give a more familiar example, which
is when the surface of the ocean is 'sucked up' by the low pressure in
the eye. Except the tsunami is much worse, as it arrives all at once,
not gradually building up over hours like an approaching hurricane.

Think 'instant temporary global warming raising water level by 20' or
more'.

Mike
--
http://www.corestore.org
"All I know is that I'm being sued for unfair business practices by Microsoft. Hello pot? It's kettle on line two" -
Michael Robertson

Lee Bell wrote:

> Since we know of the deaths and devastation caused by these waves, it's easy
> to say that they are not trivial. On the other hand, we've all seen
> pictures of people surfing on waves of comparable height. It's not clear
> why a Tsunami is so different, but it's apparent that they were.

The speed. Let your belly be hit by one liter of water travelling at 200
mph.
Matthias

Lee Bell wrote:
>>>? >Tidal waves as high as five metres hit Penang and several other
>>>? >Malaysian islands following the 8.9-magnitude earthquake near
>>>? >Indonesia's Sumatra island.
>>>?
>>>? So what's a 5-6m tsunami wave like compared to a regular one? And is
>>>it
>>>? a one shot deal, or does it come in a set?
>>>?
>>>? For one of the largest earthquakes ever, I guess I thought it would be
>>>much bigger.
>>>
>>>Large is relative. A 20' wave still isn't trivial.
>>>
>>
>>To say the least, Alan. I do not know the physics of wave energy, but I
>>remember reading that a 4' wave on one mile of coast generates 35,000 hp
>>of energy. I'm sure that is logarithmic with a 20' wave.
>
>
> Since we know of the deaths and devastation caused by these waves, it's easy
> to say that they are not trivial. On the other hand, we've all seen
> pictures of people surfing on waves of comparable height. It's not clear
> why a Tsunami is so different, but it's apparent that they were.
>
> Lee
>
>

Lee,

First, the speed that the waves are travelling (much greater) means that
they hit the coast with much more energy. Second, the waves are from one
end of the horizon to the other, and not caused by local topography. So
they hit in areas not normally subject to such large waves. Of course,
in these areas that are normally safe from large waves ... this is where
us smart humans decide to build resorts, fishing villages, etc. Thus the
result.

I don't want to trivialize the disaster. These things can seem beyond
comprehension. However, land use planners will tell you that it is
predictable that they will occur, although you never know exactly when.
The where is more certain. The Japanese have warning systems in place -
they know through past experience that certain cities are vulnerable.

The majority of human civilization developed in coastal areas, and the
concentration is still there. So long as we build in flood plains and
along coast lines, then hurricanes, floods, tsunamis and erosion will
continue to wreak havoc.

Bart F.

Mike Ross <mike@corestore.org> wrote:
>OK.
>
>Normal waves:
>
>------/\---/\---/\----
>
>Go up, down, up, down - individual waves may be (say) 20' from crest
>to trough and 50' long from one crest to the next.
>
>Tsunami:
>
> --------- (a mile or more) --------
> / \
>-------- -------------
>
>It's not really a 'wave' at all, as we normally think of waves - it's
>a huge mass of displaced water. It's much more like the storm surge
>beneath the eye of a hurricane, to give a more familiar example, which

Nice ASCII art!
--
Jason O'Rourke www.jor.com

Nobody wrote:

> I don't want to trivialize the disaster. These things can seem beyond

> comprehension. However, land use planners will tell you that it is
> predictable that they will occur, although you never know exactly
when.

Like the Big One expected in California?

> Bart F.

Forget about the land planners.


That's a piece of trivia I picked up from the South China Morning
Post (December 27) this morning, while in Hong Kong. It was still
hoDecember 27 when I got home more than 24 hours later.

The 10 largest earthqukes since 1900 by magnitude:

March 22 1960: Chile 9.5. 5000 killed 2 million homeless.
March 28 1966: Alaska 9.2. claimed 125 lives.
March 9 1957: Alaska 9.1. No live lost apparently.
Nov 4 1952: Russia 9.0. No lives were lost.

Dec 26 2004: Indonesia 8.9. Current estimate of lives lost
exceeded 10,000 and growing by the day.

-- Bob.

Joe English <jenglish@wisperhome.com> wrote:
>
> How much time passed from the earthquake to the Tsunami?

In some areas, not all that much time at all. The quake hit at 7:59am
local time. Reportedly 33 minutes later, it hit the coastal region of
Aceh in Sumatra. Phuket appears to have been hit within the first hour.

Generally speaking, the delay times were slightly more than the nominal
maximum deepwater speed of a Tsunami of 500mph. Thus, a location 1500
miles away would be hit no earlier than 3 hours after the quake. This
is enough time to issue a warning if you have the technology in place,
but in 3rd World types of areas, its unlikely that you'll be able to
successfully disseminate a warning.

FWIW, the Tsnunami was detected on tidal gages 5,000 miles away in New
Zealand, approximately 17 hours after quake (= 300mph average velocity).
Fortunately, it was only 4"-12" in height, probably in no small part
because it had to dissipatively warp around Australia to get there. It
should theoretically have also been detectable in the Atlantic too.



> You would think that they knew it was coming from aerial
> surveillance of the area.

It is rare to see what you weren't even looking for.

The Pacific basin has a detect/warning system, because ~95% of all known
Tsunami's occur there. The Indian Ocean basin doesn't have such a
network, nor does the Atlantic Ocean.

The effective fallback system is a Siesmologist somewhere whose
equipment detects the quake, which then gets plotted to an undersea
location, and some deductive reasoning says to make some phone calls.
Yesterday's news reports alluded to some warning phone calls being
initiated, but lacking a "hot line", it would have gotten bogged down.
I did see one news report that claimed that at least one of the resort
hotels somewhere did try to evacuate their beach before the wave hit.


> Does/Can a tsunami be generated from the epicenter or miles away or
> just anywhere in the general area?

I believe that it has to generally be near the epicenter, as the basic
cause is that the ground has shifted, and the water over that location
is raised in elevation, so it starts to flow downhill (away).



-hh

On Mon, 27 Dec 2004 08:19:52 -0600, Joe English wrote:


> Wasn't Mossman going to Thailand to dive over XMAS? Does anyone
> remember or know?

http://groups-beta.google.com/group/...14c240ecf1fddf

Randy Buckner wrote:
> "Reef Fish" <Large_Nassau_Grouper@Yahoo.com> wrote in message

> > The local CNN breaking news (in Hong Kong) reported at least 1,700
dead
> > in Sri Lanka (as opposed to the 2,143 reported on the web), and
that
> > the resort of Phuket and the Maldives was badly hit.

That was two days ago. The estimate of death toll caused by the
quake and resulting tsunamis exceeded 22,000 this morning!
> >
> Very sad indeed. I just read this:
>
> Paradise destroyed
>
> Thai authorities say more than 200 are feared dead, and hundreds are
missing
> after the massive waves swept through coastal areas, including Krabi
and the
> popular resort islands of Phuket and Phi Phi.
>
> One witness said Phuket's famed Laguna Beach resort area is
"completely
> gone." The area provides 40 percent of Thailand's $10 billion annual
tourist
> income.
>
> Among the missing were a number of scuba divers exploring the Emerald
Cave
> off Phuket's coast. Officials say the final toll in Thailand may be
closer
> to 1,000.
>
> Buck

I read something in the Asian papers that some scuba divers diving the
famed Emerlad Cave (where the exit is through a tunnel at depth, guided
by ambient light above) were rescued while others were lost diving that
site.

I haven't heard much about Bali and how it was affected by this event.
I am doubly glad I had the chance to dive there in April and
experienced
the incredible drifts/currents and seeing my first mola mola there!

I suspect diving in Indonesia and the Maldives will be forever changed
by this natural disaster.

-- Bob.