What would happen to this floating platform in a Tsunami?

[Dr.Smart]

Here is a hypothetical floating platform (not to size). What would happen to it?



The light blue like is a Tsunami as powerful as the one that hit Japan.

[Mr Efficiency]

Err.....It depends. At the moment I think a more important question is what can be done to try and ease what is looking like an immense catastrophe in Japan. Been a bad run of disasters in the Pacific Basin, this easily the worst. Pray that nuke plant doesn't blow.

[Dr.Smart]

Originally Posted by Mr Efficiency

Err.....It depends. At the moment I think a more important question is what can be done to try and ease what is looking like an immense catastrophe in Japan. Been a bad run of disasters in the Pacific Basin, this easily the worst. Pray that nuke plant doesn't blow.

Actually we are planing on building something similar in the future. And the Tsunami in Japan scared us. We don't want to end up dead.

Would it pass harmlessly underneath?

[Mr Efficiency]

Tsunami waves are analagous to the type of waves that run well up wide, flattish surf beaches when a big swell is running. In other words you get a large volume of water physically moving forward, unlike the situation in deep water where the movement is pretty well in the vertical plane, up and down. So the best plan for boats in an area known to be about to be struck, is move out into deep water. Your chances of being caught up in a tsunami whilst on board a boat are statistically very tiny, within a human lifetime.

[Mr Efficiency]

Historically Japan has been a frequent host to Tsunami, it is a Japanese word meaning " harbour wave "

[TeddyDiver]

Originally Posted by Dr.Smart

Here is a hypothetical floating platform (not to size). What would happen to it?

The most important factor is the depth of water.. Deep enough you don't even know anything unusual has happened..

[daiquiri]

If the platform is freely floating (no moorings), I guess it would surf down the wave like a surfboard. It would depend on the underwater hull shape. And at the end it would hit the shore.

[CatBuilder]

At 250 miles out to sea, not a damn thing would happen to the platform in a tsunami.

Tsunamis travel at around 500MPH through the water and have little to no amplitude in their waveform. They don't do anything at sea, which is why you take your boat to sea if there is going to be one.

They only rear up as the water gets shallow.

[daiquiri]

Damn, that's absolutely right. I wasn't paying attention to the numbers in the pic.

[Submarine Tom]

Nothing.

-Tom

[cthippo]

Originally Posted by Mr Efficiency

Historically Japan has been a frequent host to Tsunami, it is a Japanese word meaning " harbour wave "

We quit using the inaccurate term "tidal wave" and instead moved to an inaccurate term in another language. Who says the language isn't progressing?

[jehardiman]

I agree with Teddy and Cat, 250 NM offshore and most like you are off the shelf. If you look at the buoy data from this one, you seen an amplitude of ~ 3.5 ft (wave height ~7 ft) and a wave length of 200-300 miles....you wouldn't even notice it if you didn't have the sensors. Now if you were on shelf in shoal water like the Arafura Sea or Sunda Shelf, I would need to run some numbers but as I recall from the Christmas '04 quake, it really wasn't that much after the initial break.

Edit: BTW 0.25 land mile is ~ 1350 ft, or slightly longer than the length of a VLCC or CVN. CVN 73 was in Yokosuka for this one and is ok.

[PAR]

If you were in the water (diving) you'd probably feel it go past, but that's it that far off shore. I have a client that happened to be diving when the Sumatra tidal wave roared past. He said he felt like he was on an elevator when it just starts or an airplane that drops suddenly for an instant. At the time he thought it was a weird current, as they were on the shelf, but about 40 miles off shore.

[Frosty]

Being in the tsunami I can tell you of lots of boats off shore that never knew anything about it. A tsunami is not a wave , it is a new level of water.

people say it was 20 feet high,--no it bounced off a rock 20 feet high.

I looked at the tsunami coming for me --it was 4 feet high but was 1 kilometer long behind , a new level of water.

it does'nt stop like a wave but out at sea you don't notice anything.

What did I do ?-- nothing --I could not start a engines and untie the boat in the time I had, nothing happened but 3 high and low tides in 4 hours.

2 marinas with only one inlet were totally 100% destroyed, the one I was in was in 6 Km away behind a wall and water could get in and out. I had no damage.

[hoytedow]

Originally Posted by Frosty

Being in the tsunami I can tell you of lots of boats off shore that never knew anything about it. A tsunami is not a wave , it is a new level of water.

people say it was 20 feet high,--no it bounced off a rock 20 feet high.

I looked at the tsunami coming for me --it was 4 feet high but was 1 kilometer long behind , a new level of water.

it does'nt stop like a wave but out at sea you don't notice anything.

What did I do ?-- nothing --I could not start a engines and untie the boat in the time I had, nothing happened but 3 high and low tides in 4 hours.

2 marinas with only one inlet were totally 100% destroyed, the one I was in was in 6 Km away behind a wall and water could get in and out. I had no damage.

You were fortunate. Thank God.