Video of tsunami in Japan | Hacker News Reader

Video of tsunami in Japan

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310 pointsthornjm67 comments

Color me educated. I used to think that a tsunami was a giant wave which would splash, and then it's gone. I didn't know/realize how slow-moving but MASSIVE this was.

So what happens to all this water? Does it eventually go back into the sea the way it came in? Or is this the default sea-level now?

From the wiki article, by the time a large tsunami reaches the shore, it has a wavelength of ~20km, taking ~1-2 minutes to reach the peak of the wave.

And yeah, in the long term, most of the water will go back out to sea (or evaporate off). Of course, areas that were below sea-level before hand, will now be big ponds until they're drained, but by and large, the water will withdraw (which does extra damage!).

> areas that were below sea-level before hand Some areas became below sea-level _after_ the quake. The land sank a maximum of 70cm.

Yeah, I think a good number of people don't understand how tsunamis work, even here in Hawaii. During an emergency, radio and TV broadcasters here try to explain that tsunamis are more like solid walls of water - i.e. the entire ocean lifting up six feet, but of course, people don't listen. That makes it very dangerous when there's a tsunami warning (like last Thursday), because people think, oh, it's just like surfing! six feet is not even that much!, which means that some people don't evacuate. Plus there are always some geniuses that insist on sitting next to the shoreline, and the police have to shoo them away.

Even "wall of water" is misleading, as that's not what it is at all. A horizontal wall perhaps, but not a vertical one like in the finale of Abyss.

One way I've used to explain it is to imagine you're on a boat at sea and a tsunami passes under you. You wouldn't even notice.

The boat would slowly rise a few feet and stay there for a few minutes as this huge mass of water passed under it, then slowly drop back down to its original height, and no one would be the wiser.

It's not until the mass of water hits the shore and keeps piling on for several minutes, that people can see what it is.

Reminds me a little of this from 2004, where the photographer and his gf or wife just seem to make it out alive: http://www.youtube.com/watch?v=Gbq412haY1c

Scary, scary stuff.

And somehow we think we are masters of the planet. When nature's true forces come to bear there isn't much we have ever built that stands in the way.

Here's to wishing all those that survived a speedy recovery and my condolences to those who know people who didn't make it.

To be fair, theres nothing of nature's that stands in nature's way. It ruins it's own shit too. It's all entropy right?

Ruins or makes stronger?

Right.

Can't find the source from months back, but, us humans were constantly trying to stop all forest fires in near-populated area's, which were needed (by nature) to clear area's for other vegetation which can't grow in certain over abundances of tree species.

Was that too simplified? Sources. Basically, soil enrichment, the "choking" of other plant vegetation if fires do not occur at intervals, etc. Its the same argument of overpopulation of deers = starvation of deers, since we've taken out the natural predators of wolves in many area's, hunting is a necessity.

http://www.springerlink.com/content/q8755xw004285060/ http://www.enviroliteracy.org/article.php/46.html

http://www.infoplease.com/spot/forestfire1.html "Forest fires can have beneficial effects. Charcoal enriches soil, and some plant species flourish in the wake of conflagrations. The cones of the jack pine tree, for instance, will not release their seeds unless exposed to intense heat. Sequoia or Douglas fir trees grow best in open sunlight areas, such as those cleared by fire.

Natural fires also remove dead wood and tangled brush. For these reasons, the Forest Service of the U.S. Department of Agriculture, which administers 17% of all U.S. forest reserves, often allows fires, especially when started by lightning, to burn in carefully monitored areas."

Edit: The Parent (up deus) post stated "Nature ruins its own shit right?" not necessarily if you look at the world as an entire ecosystem. I guess I am confused as to its upvotes, when it means absolutely nothing.

Holy shit there comes an s!

Although a very serious situation, couldn't help but note Paul Kedrosky's observation:

http://twitter.com/#!/pkedrosky/status/46604765890752512

I wonder what happened to the poor man trapped at the end of the video...

Whole buildings moving at ~4:30 in.

Was going to post the same - it gets really bad at 4:30. Cleaning up this mess is going to cost several GDP's.

$35bn apparently

http://online.wsj.com/article/SB1000142405274870402750457619...

That doesn't cover any of the damage from the tsunami or radiation, which should both add quite a bit. The government's also on the hook for a lot of the damage to residential buildings (some of which we saw float by in the linked video).

I wonder if an artificial tsunami of the same scale can be achieved my setting off a nuclear bomb underwater? This seems to be more damaging (infrastructure-wise) than a direct nuke hit.

It's been tried (kinda). Doesn't really work apparently.

http://en.wikipedia.org/wiki/Project_Seal

According to wikipedia scale an 8.8 magnitude earthquake has approximately the same energy release as a 288 megaton nuke. Since the largest nuclear bomb ever was 100 megaton and a 35km radius for the zone of total destruction, direct bombing is almost certainly more damaging.

I (morbidly) wonder if it would be possible to set off a tsunami with just the explosion, without necessarily the ground movement. It would seem to me that a lot of the earthquake's energy release would go into shaking the ground.

Anyway, the story of that bomb is interesting too: http://en.wikipedia.org/wiki/Tsar_Bomba

You could, perhaps, trigger an underwater quake by bombing a fault zone with a large enough nuke (or sequence them as to compound the shock)

Can you post the link? The USGS says 25,000 nukes would be needed to match the power of a 9.0 earthquake.

http://earthquake.usgs.gov/learn/faq/?faqID=33

It went from zero to complete chaos in about 3 minutes. That is just nuts.

Do not mess with water.

The beginning of the flood looks innocuous enough, but it keeps on coming...

More tsunamis for the morbidly curious:

https://secure.wikimedia.org/wikipedia/en/wiki/Megatsunami

Record stands at 524m high.

Just to be clear, a megatsunami is not usually caused by earthquakes, but rather other events and are very rare.

Normal tsunami: https://secure.wikimedia.org/wikipedia/en/wiki/Tsunami

I like how the water level rises from the beginning to the end, at the start there's just a few cars moving a little and you're like "this isn't so bad", and then at the end water is gushing in with cars and buildings rolling around in a cacophony of madness, even the camera man has retreated to well above water level at this point.

What is the possibility that the guy driving the car at the beginning outraced the tsunami?

Wow. This is just horrific. My heart goes out to Japan. Hang in there guys!

Opera displays a Blank Page, Chrome attempts to play the video with no controls and Firefox tries do download the mp4 file.

What on earth is going on here?

EDIT: it was just taking too damn long. Could be my connection, though.

My Firefox (3.6.13 on OS X) decided to overlay the video extending it outside the page bounds and covering the status bar, and it will not go away now that I closed the tab, remaining overlaid over all the other pages when I switch tabs.

A-, Would not click again.

So, download and save it. (Right click, save link as.)

Then open it in your favorite video player. Use VLC if you don't have one.

VLC can play it directly too, but it's probably easier to just download it.

It works here in Opera on Windows 7. My guess is that QuickTime is messing with you.

In Chrome I get controls when I mouseover the video (11.0.696.3 on Mac).

On Windows Chrome does not give you controls, but you can right click to pause/unpause it at least.

My brand new unrooted NOOKcolor worked great

Transcoded to Flash video. I'll keep it up unless my host has a problem about copyright... http://deathbycomputers.co.uk/crapandstuff/1605260179420_262...

Why not transcode to WebM?

The video is now gone. Does anyone know of another way to find it?

I remember when I was really little my dad telling me that water was so much scarier than fire because it can't be stopped... Looks like proof.

Youtubed: http://www.youtube.com/watch?v=bzmRyyAbBIg

Now removed :/

Dead already.

"This video contains content from TV Asahi Corporation, who has blocked it on copyright grounds."

Is there a link to this video with a player/context? Direct link to the .mp4 is unusual and somewhat hard to share.

http://reut.rs/eTSZoM

I wonder how do insurance companies survive such natural disasters?

What part of Japan is this?

Same video appears on BBC ...

http://www.bbc.co.uk/news/world-asia-pacific-12722026

"Footage has emerged of Friday's tsunami sweeping through Kesennuma City in Miyagi Prefecture, north-eastern Japan."

Mirror:

http://www.machinesentience.com/miscvideos/amazing_video_of_...

Not sure why anyone would want to censor this sort of thing off of youtube, my guess is they are trying to Streisand Effect themselves.

I chuckled a bit when the parked cars started bobbing, then made their way to the 'street' and floated away as if driving off to work. Everything else was horrifying.

What was wrong with the term "Tidal Wave"? It looks like a huge tide rolling in.

They are nothing to do with tides.

Tsunami means harbor wave which is a good description - at sea they are almost unnoticeable - it'sonly when the water is concentrated on a shore - or in a harbor that they have such an effect

Not really getting the "harbor" connection. And it still looks like a big surge tide rolling in.

It's because the tsunami only becomes visible when it hits your harbors. They used to be called "tidal waves," but the term is inaccurate — that's why it isn't used anymore. They're not like normal waves out at sea, and they have nothing to do with the tides. The fact that it "looks like a big surge side rolling" in does not actually make it tidal.

Did you know Cotton Candy isn't made from cotton?

That doesn't make it any more valid to call it a tidal wave. I would think someone on HN would be happy that a misnomer is no longer being used.

It only becomes a visible problem in harbours (or otherwise in shallow waters).

It looks like a tidal wave in the sense that it's a lot of water moving in a given direction. The mechanism causing it is not the same at all, so the name tidal wave is misleading.

As an example a friend of mine was on a boat during the massive 2004 tsunami, but since he was a few miles off the coast where the water was deep he didn't even notice the tsunami sweeping under his boat. Once it hit land it did massive damage.

I think Rubashov understands that the process generating these waves is nothing like that which generates the tides, but correctly observes that the process resembles a tide--huge volumes of water rising, then falling back into the sea--more closely than ordinary waves, no matter their size.

other day friend quipped "Japanese are so smart designing quake proof bdgs". seems they forgot the tsunami thing after.

Go read patio11 blog post and don't be a douche.

They didn't forget - a Tsunami is a block of water a meter high and several km deep moving at 800km/h.

That's a few BILLION tons of water moving at the speed of a jet aircraft - try designing against that.

Important first correction. The wave moves at that speed. The water itself does not. It mostly bobs up and down slightly.

Important second correction. The height of the tsunami when it hits shore is not the height of the tsunami when it is out at sea. All waves, tsunamis included, rise up when the bottom of the water starts to compress the bottom of the wave, compressing its energy into a smaller volume.

With these corrections, a tsunami out at sea is a wave a few cm high moving at 800 km/h with the water barely moving, but with the whole water column moving. It is therefore entirely conceivable that a well-built dike could withstand such a wave.

Obviously such dikes were not in place this time, but the feasibility of building them has been investigated. By Japanese scientists no less. See http://www.pwri.go.jp/eng/ujnr/joint/37/paper/13kato.pdf for one paper on the topic.

There actually were such dikes in some places, you can see them overflowing in some of the videos.

The thing is, you have to decide how high a dike you're willing to pay for, which is a cost vs. remaining risk tradeoff. The risk of the 5th strongest quake ever recorded occuring right before your piece of the coast was apparently considered acceptable - Hindsight always wins.

Thanks - I was trying to get across that this is a block of water the mass of a small mountain dropping on you. You can earthquake proof a building but you can't do much against this.

Even a regular storm surge in the north sea needs some serious mega-project engineering to protect a single river/city. Protecting the entire coastline of Japan against a Tsunami would be tricky

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