Liquefaction from the Sendai earthquake – a remarkable video

http://blogs.agu.org/landslideblog/2011/03/17/liquefaction-from-the-sendai-earthquake/

by elliottcarlson • 15 years ago

155 29 15 years ago

blogs.agu.org

wmwong• 15 years ago

For those of us who are not familiar with the term liquefaction. In simple terms, I think it means the soil becomes like quick sand because of the earthquake.

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

michaelcampbell3• 15 years ago

Exactly. Liquefaction is not water coming up from the ground, although that's a side effect of it.

martinkallstrom• 15 years ago

Even more startling is the liquefaction happening in Christchurch:

http://www.youtube.com/watch?v=2WoKu5VxKgs

Here is an awesome video by a Christchurcher showing how the sediments pouring up through earthquake cracks have the perfect mixture of water and soil to be prone to liquefaction:

http://www.youtube.com/watch?v=1KqlAMWMjOE

NZ_Matt• 15 years ago

I spent a week clearing this crap out of people back yards with the student army of volunteers. They estimate 200000 tonnes of the silt had to be cleared.

Here's an example of the silt coming out of the ground minutes after the quake. http://www.youtube.com/watch?v=e_twYpUJl9o

And here's a good explanation http://mandenomusings.wordpress.com/2011/03/03/christchurch-...

aaronbrethorst2• 15 years ago

That is really disturbing, and it reminds me of something I just read the other day.

For any Seattle startup folks, just remember that all of Pioneer Square (and then some...) is a liquefaction zone[1]. Also, don't forget that the Viaduct is a death trap, and you really are better off never setting foot (or wheel, I guess) on it.

[1] http://www.thestranger.com/slog/archives/2011/03/16/more-sea...

jarin• 15 years ago

You should also stay in an underground bunker and never go outside, because dude do you have any idea how many asteroids are out there?? The entire surface of the Earth is an Asteroid Impact Zone!

aaronbrethorst2• 15 years ago

or just stay off the viaduct. that seems far more straightforward :)

InclinedPlane2• 15 years ago

The 520 bridge is also very vulnerable to earthquakes (the primary reason why it's being replaced).

sukuriant• 15 years ago

You mean that bridge that's about a foot above the water level and, when there's a really turbulent storm, can have rough water on one side and calm water on the other, and have waves literally crashing over the cars from the one side of the water?

Nooo, I would have never thought that bridge would be dangerous in an earthquake! </sarcasm>

I'm not intending to mock you, though it's probably coming off that way. Outside of the cool special effects during a storm (seriously, the 'rough water, bridge, calm water' effect is quite eerie), I have no idea why that bridge was built the way it was.

Anechoic• 15 years ago

> For any Seattle startup folks, just remember that all of Pioneer Square (and then some...) is a liquefaction zone

For that matter, so is a large chunk of the Bay Area.

Whether it's earthquakes, wildfires, bizzards, tornados, hurricanes, etc there is always gouing to be something pretty much wherever you settle.

Florin_Andrei• 15 years ago

> For that matter, so is a large chunk of the Bay Area.

More specific?

malesniak• 15 years ago

Quite a remarkable video... a little less so when you get to the end and he informs you of the history of Tokyo Central Park (reclaimed land). Still... unbelievable. Much less dramatic that the Google images of entire communities washed from the Earth... devastating.

dstein• 15 years ago

That's the most casual walk through a Japanese park during an earthquake I can imagine.

BasDirks• 15 years ago

"a sombrero, and a huge clock"

Is this Chuck Norris wielding the camera?

delinka2• 15 years ago

I've never experienced an earthquake. As such, the cracks and drifting earth make me doubt the reality of such a video. Does this drifting actually occur at the surface like that? Edit: speeling ;-)

michaelcampbell3• 15 years ago

I've been in 2 about 20 years ago; both ~5.1. If memory serves there were 2 distict types of shaking. The first was a fairly high frequency vibration that shook the walls and mimic what you see in movies; $#@! flying off shelves, etc.

The second came a few seconds later, and was a slow back and forth horizontal movement of the ground. I remember it being a bit faster frequency than that video shows, maybe about 1Hz, but it seemed like the ground was just moving fairly slowly back and forth a few inches.

delinka2• 15 years ago

I've heard many accounts of these phenomena from others. What I'm having difficulty with is the relative motion of the different pieces of earth. I live on pretty solid ground away from active fault lines. If one of our minor fault lines ever acted up, I could certainly imagine the kind of motion you mention. But if my property "cracked," I'd expect to feel the swaying motion and that each piece of my yard would move in the same direction preventing me seeing the motion. On further consideration that the park in the video is built on a former bay, I supposed the quake could be making the dirt float around on the mushy underside.

The first thing I noticed was an oddness about the crack in the sidewalk. It seems to have cracked perfectly along some crack line that's outside of the sidewalk (not likely - just because dirt cracks underneath doesn't mean the concrete will crack exactly where the dirt does) and there seems to be some rubbery surface where the crack ends in the sidewalk (it stretches as the parts of earth move in different directions.) Not like the pure concrete sidewalks I'm accustomed to, but Tokyo is worlds away and maybe it's not just concrete.

P.S. Why the downvoting on my original post? Is it not a valid question?

po• 15 years ago

I was in the earthquake in Tokyo (a few kilometers from Odaiba where that video was likely taken) and I can say I believe it. Out this far from the epicenter it felt very wobbly. It was like my house was on a block of Jell-o. It felt like a 1-3 htz wave. There was a good three minutes of very strong movement and another severe aftershock a 10-20 minutes afterward.

BTW, The girl having a picnic with her boyfriend when the video starts is shouting こわい (kowai) which means "scary!".

kazuya2• 15 years ago

I've been in Tokyo for more than 20 years but I cannot tell which 'Central Park' this is.

Shinjuku Central Park is a well known one and it is surrounded by skyscrapers, but this one doesn't have them.

Any hints?

rheide• 15 years ago

I think it might be near Odaiba.

brianbreslin• 15 years ago

he says it is in reclaimed part of tokyo bay. so wouldn't have skyscrapers ALL around, but should have some in a few of the shots.

kazuya2• 15 years ago

Ah I didn't notice it as I turned audio off.

Now I managed to spot it. The park is actually Makuhari Kaihin Park (幕張海浜公園) in Chiba, not in Tokyo (that's why I was not aware of it).

And yes it is on reclaimed land, the homepage of the park in fact mentions liquefaction.

Liquefaction from the Sendai earthquake – a remarkable video

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