Quations about the tsunami

[echnidna]

So are there any lessons from the tsunami.
While the waves were reported as only being 6ft high why were they able to write off 2 storey buildings?
How far inland did they travel?
What land elevation was safe?

Expect all those who live on or near the coast may be interested.
Specially those northeners whose barrier reef is dying. When it is dead what protection do they have?

[Sir Stinkalot]

echnidna,

The Stinkette and I were in Thailand for our honeymoon and we stayed at Phi Phi Island .... one of the worst hit areas of Thailand, luckly we flew out Christmas Eve. The quality of construction wasn't anywhere the same standards that we expect here in Australia .... it was only the higher end hotels ... often owned by Western companys I would think .... that were of a higher quality masonry construction and many of these stayed up.

I think that many buildings were lost due to the construction techniques which was obviously limited by budget, skilled labour and materials.

Stinky

[bitingmidge]

Specially those northeners whose barrier reef is dying. When it is dead what protection do they have?

New Zealand!!

You probably need to see a model or picture to see how waves build up as they get into shallower water, and I'll leave that one for Doctor Karl.

What can you do? Friends of ours lived on the beach front at Phuket, wife and kids were back in Queensland visiting family, and he'd gone to town to an appointment when their house disappeared. That's the only successful strategy- don't be there!

One stat had a pre-historic wave hitting the east coast of NSW at 120 METRES high.... dont' try to swim away from that one either!

But what do YOU do if you go to live in the mountains and get hit by a meteorite... chances are probably similar!

I live at sea level, (house floor is 2.4m above highest astronomical tide) and I looked around for a few days, realised that I'd have to learn to swim better, then got on with life!

Cheers,

P :D

[TassieKiwi]

Look here:

http://www.eri.u-tokyo.ac.jp/namegaya/sumatera/surveylog/eindex.htm

note the 36 metre high waves recorded on the west coast of Sumatra. No-one could run from that. No wonder the whole coast was wiped off the face of the earth - frightening.

[Zed]

answers to your questions below.

While the waves were reported as only being 6ft high why were they able to write off 2 storey buildings?

mass x velocity ... lots of water.... I think its netwons 2nd law (?) that sez every action has an equal and opposite reaction (m1u1 + m2u2 = m1v1 +m2v2) I think the formula is right - forgive my high school physics - what this means is that the water keeps on trucking until something stops it - "stops it" means something that is big enough and powerful enough to overcome the energy the water is carrying. stopping can be a gradual braking ( as per random objects slowing it down) or a sudden stop (like a big freakking building.) to answer your direct question think of it as erosion and undermining foundations.....

How far inland did they travel?
quite a far way - not sure exactly - it depends on the elevation and the slope

What land elevation was safe?

I think people on cliffs 20m high right on the sea edge watched the waves humpin' past. although in a really massive event the waves would climb up the hill / cliff face until its energy was expended - even if the cliff is at 90deg!

whats the old joke about what do you do if you want sea side real estate in sydney ? buy in Parramatta and wait!


there was this show about physics recently that some pommie wanker put himself into all sorts of stupid positions to prove various points (like sitting in a freezer to see what temp his body dropped to before he got hypothermia, sitting in the desert and deyhdrating)... anyway one of the things he did was stand in front of a dam whilst they steadily increased the flow of water thru the sluice gates - it only got to below his knees before he fell over - lots of mass and power.

here endeth the lesson - no dont thank me just a greenie will do.

[ubeaut]

Echidna - I think it was 6 metres high not 6 ft...... Big difference and not just a wave but a wall of water followed by the full fource of the ocean.

Bloody scary.

Lessons - You can run but you can't hide. Live in inland Australia or stay on the great divide or just forget about it and get on with life.

[TassieKiwi]

Also search for videos of the wave. SOme of them are very chilling, and make you think 'what would I have done'?

[Iain]

I'm in trouble then, 2km from Westernport Bay, flat as a dunnymans hat, what hope have I got apart from running up the bloody big hill behind me.

[Wongo]

I have been watching a show called “Zero hour” on Channel 7. It shows how some of the worst crimes committed in recent time. 911, US high school shooting, Tokyo gas attack and Russian nuclear accident. I got so worried and wonder what the world has become. And we have earthquake, tsunami, flood etc.

So what do I do? Find a place which is away from the ocean, volcano, don’t fly, don’t let my kid go to school, do catch a train to work or don’t work at all ….. Yes, there is a place that I can go and it is safe enough - graveyard.

There is very little I can do so I’ll just get on with life and worry a little bit.

[Zed]

Also search for videos of the wave. SOme of them are very chilling, and make you think 'what would I have done'?


you would die, unless you can swim very fast or fly like the underpant brigade.

[jackiew]

one of the articles that I read talked about a place where they'd planted a whole load of trees between the village and the sea rather than had the village right next to the sea.

http://www.planetark.com/dailynewsstory.cfm/newsid/29275/story.htm

[AlexS]

About 30 years ago I was in Bougainville (PNG) during an earthquake and resultant tsunami. The quake was quite a long way off, and the tsunami a lot smaller, but fortunately, we had a hydrographic team that, thanks to the initiative of a local trainee, took & recorded some interesting observations.

Where it hit the west coast, the tsunami was about 1m, and passed under most of the local houses without damaging them. It did remove some livestock, boats etc, and some houses were damaged by debris.

The team were on an outcamp on the Jaba river, about 10km from the west coast. The tsunami came up the river like a tidal bore, then, a few minutes later, came down, again like a tidal bore. From the time of the first wave, the crew started taking water samples.

The River normally had a sediment concentration of up to about 10% due to mine tailings. However, when the second wave came down, the concentration dropped dramatically, and the salinity was much lower than seawater.

About 10km above the camp was a large area of saturated tailings that were like quicksand. When we later surveyed it we found that it had dropped by about 1m, and was no longer saturated. Our conclusion was that the quake had caused the saturated tailings to compact and the fresh water had been shaken out of them.

I'd love to go back there now and see the results of many years of non-mining on the river. Anyone on the board been there?

[ozwinner]

Everybody run!!!! (http://www.iris.edu/seismon/) :eek:


Al

[ozwinner]

And again!! (http://en.wikipedia.org/wiki/2004_Indian_Ocean_earthquake)


Al

[Kev Y.]

While the waves were reported as only being 6ft high why were they able to write off 2 storey buildings?

maybe some one got their imperial and metric measuring systems mixed up?




How far inland did they travel?

It all depends how big the island is. I think I am safe here, I have the strezlecki ranges between me and the ocean.




What land elevation was safe?

I am however thinking about moving to the top of mount Bulla. Have you seen "the day after tomorrow"?

[Pat]

Having a captain's at the site, that you provided Al, I think that we may see more of our eastern cousins migrating westward as the two little knolls get the living shiite shaken out of them! :)

Pat

(I am, of course, refering to our New Zealand neighbours, for the non - Australasian members :D )

[kiwigeo]

So are there any lessons from the tsunami.
While the waves were reported as only being 6ft high why were they able to write off 2 storey buildings?
How far inland did they travel?
What land elevation was safe?



If you go to the beach and watch the waves coming in youll notice they dont seem that high as they roll through deep water. As they approach the beach and water depth decreases the height of the waves increases. Same thing happens with a tsunami but on as much larger scale...a lot more energy involved than a wind driven wave.

The waves get even higher if they are laterall restricted...eg if theyre tearing up a street or through a built up area.

How far inland do they travel....depends on wave size and topography theyre travelling over.

What land elevation is safe? Cant give you a number. I youre getting worried then you have two options: 1. move to a higher location or 2. keep a pair of running shoes by your bed and start injecting yourself with steroids.

Martin

[kiwigeo]

Having a captain's at the site, that you provided Al, I think that we may see more of our eastern cousins migrating westward as the two little knolls get the living shiite shaken out of them! :)

Pat

(I am, of course, refering to our New Zealand neighbours, for the non - Australasian members :D )

Um theres actually three little knolls......you left out Stewart Island.

Looking at the topography of Australia and NZ I think Id be staying in NZ if a tsunami was heading my way.....the country's generally alot higher than Australia.