Giant Tidal Wave in Thailand.....

In article <cqnm9a$1nth$1@agate.berkeley.edu>, Jason O'Rourke
<jor@soda.csua.berkeley.edu> wrote:

€ Alan Street <agstreet@nonono_san.rr.com> 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.


----------------

"The strongest tsunami in known history was produced by the eruption
of the Krakatau of the Sunda Island group in 1883. It reached a wave
height of 35*m and claimed 36,830 lives. Four tsunamis with heights in
excess of 30*m have been documented in the Pacific Ocean since 684 A.D.
A strong tsunami in the Atlantic Ocean was observed in 1755 after an
earthquake near Lisbon (Portugal).

In the vicinity of the epicentre of an earthquake, tsunamis can result
in extreme wave heights. Once they reach the open ocean and travel
through deep water tsunamis have extremely small amplitudes but travel
fast, in 4000*m water depth at about 700*km/h. (This speed can be
estimated by using the wave speed equation given above: We have g = 9.8
m s-1, h = 4000 m, so (9.8 x 4000)1/2= 200 ms-1= 700 km/h.) On
approaching a coast they build up wave height again through shoaling.
The period of tsunamis is in the range 10-60 minutes. Figure 10.1 shows
a record of a tsunami from an Alaskan earthquake recorded in Hawaii."

http://www.es.flinders.edu.au/~matto...lecture10.html



Here are a couple of other references:


http://www.fluidmech.net/tutorials/ocean/tsunami.htm


http://www.pdc.org/tsunami-characteristics.php

"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?


According to the Phuket Gazette,
http://www.phuketgazette.net/news/in...=2004122713520 there are 122
dead and 350 missing.

Those numbers will probably grow as time goes by.

Ian

On Mon, 27 Dec 2004 07:16:21 +0100, "Indigo"
<indigo-alien@rocketmail.com> wrote:

>
>"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?
>

Pictures.

http://soieasy.com/modules.php?set_a...bum.php&page=2

"Alan Street" <agstreet@nonono_san.rr.com> wrote in message
news:261220041903353135%agstreet@nonono_san.rr.com ...
> In article <cqnm9a$1nth$1@agate.berkeley.edu>, Jason O'Rourke
> <jor@soda.csua.berkeley.edu> wrote:
>
> ? Alan Street <agstreet@nonono_san.rr.com> 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.

Buck

Karl Denninger wrote:

>
>
>
> The problem is not really the height - its that they can be 100 miles WIDE.

It is the speed.
Tsunami waves are triggered by movements of the seabed, opposed to wind
normal driven waves.

Thus the normal math to calculate wave height/Speed/ wind/sea depth do
not apply.
Tsunamis can travel with several hundreds mph speed.

You can simulate it in your batthub. Test the difference between blowing
at the surface, and letting bounce your belly.

Matthias

Randy Buckner <Randybuckner@nospamaol.com> wrote:
>> ? 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.

but I'm not so concerned with the energy of a 4' wave over a mile of coast.
Ocean Beach just down the road from me has surfing ranging from nothing to
double overheaders. And occasionally bigger waves that aren't surfed. A storm
can give us 20'ers for a while. Doesn't harm things a bit...the coast is forged
by this range. Personally I've been out in up to 10s, though usually not
intentionally about 6-7.

This one wiped out beach resorts, so obviously it's more than that.

--
Jason O'Rourke www.jor.com

In article <cqnm9a$1nth$1@agate.berkeley.edu>,
jor@soda.csua.berkeley.edu (Jason O'Rourke) wrote:

> Alan Street <agstreet@nonono_san.rr.com> 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?

Its a series.

As the ground shakes, it causes some up and down 'piston' action that
make some waves, and then when the ground finally shifts, think of this
as the 'piston' getting stuck in the up position, which forces the
displacement of a big bubble of water.

The danger is not just the 'wave', but the total mass which acts in a
fashion similar to a Hurricane's Storm Surge.

FWIW, for this event, the biggest wave was reportedly not the first
one. It appears that the 2nd or 3rd wave was the strongest, as per
eyewitness statements.


> For one of the largest earthquakes ever, I guess I thought it would
> be much bigger.


The biggest waves reported from this Tsnunami were reported at 20m,
although I'm not sure which country these hit. Wave height can depend
on local topology forming factors.

Finally, when it comes to power, the rule of thumb is a square
relationship: doubling a wave's height means it has 4x the energy.
Thus, a 20m wave has ~~64 times the energy of a (2.5m) 8 foot wave.



-hh

>> ? >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

H. Huntzinger wrote:

> In article <cqnm9a$1nth$1@agate.berkeley.edu>,
> jor@soda.csua.berkeley.edu (Jason O'Rourke) wrote:
>
>
>>Alan Street <agstreet@nonono_san.rr.com> 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.
>>

How much time passed from the earthquake to the Tsunami? You would
think that they knew it was coming from aerial surveillance of the area.
Does/Can a tsunami be generated from the epicenter or miles away or
just anywhere in the general area?

Do they know where the Tsunami was generated, one report I read or heard
said the Tsunami was traveling at 500 mph, I hate to try to out swim that!

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

Joe English wrote:
> H. Huntzinger wrote:
>
>> In article <cqnm9a$1nth$1@agate.berkeley.edu>,
>> jor@soda.csua.berkeley.edu (Jason O'Rourke) wrote:
>>
>>
>>> Alan Street <agstreet@nonono_san.rr.com> 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.
>>>
>>>
>
> How much time passed from the earthquake to the Tsunami? You would
> think that they knew it was coming from aerial surveillance of the area.
> Does/Can a tsunami be generated from the epicenter or miles away or
> just anywhere in the general area?
>
> Do they know where the Tsunami was generated, one report I read or heard
> said the Tsunami was traveling at 500 mph, I hate to try to out swim that!
>
> Wasn't Mossman going to Thailand to dive over XMAS? Does anyone
> remember or know?

They move at 500mph in deep water but are very small. As the water
shallows the wave slows and the volume of moving water piles up so you
get a big wave, it is not moving that fast though. The overall volume
of water is not just the breaking wave but the whole mass of moving
water following, I believe this is the difference when compared to large
surf type waves - it just keeps coming.