17 March 2011
Liquefaction from the Sendai earthquake – a remarkable video
Posted by dr-dave
Update again: I have now corrected the link below so that it shows the correct Youtube location.
Update: for those who are confused by the process of liquefaction – and the comments below suggest that are many for whom this is the case – there is a video that allows one to get an idea of the process that was occurring below the surface at the park in Japan in this post.
An astonishing video has emerged on Youtube that was taken during Sendai earthquake. It shows liquefaction occurring in real time in Tokyo Central Park. It is quite, quite remarkable. Do watch beyond the first minute, when it appears that not much is happening – the real action starts about halfway through the recording:
This is quite extraordinary! Note how the cracks open and close; how the water starts to appear across the park simultaneously, and how the magnitude of the liquefaction starts to generate fountaining. Now imagine what this effect must have been like in Christchurch, where liquefaction was widespread (source):
Dave Petley is the Wilson Professor of Hazard and Risk in the Department of Geography at Durham University in the United Kingdom. His blog provides a commentary on landslide events occurring worldwide, including the landslides themselves, latest research, and conferences and meetings.
sajjad said on 18 March 2011
what suprirses me more is how calm everyone seems despite a shockingly massive earthquake. it would be normal to freak out at this, however everything seemed calm. have the japanese been drugged sluggish
Zecc said on 18 March 2011
@sajjad
What did you expect? That they would go around running in circles and flailing their arms in despair?
It’s not like the earth was suddenly disappearing from under their feet or rocks were been thrown up in the air.
I wasn’t there, but I would think this is the sort of experience that “only” makes you anxious and uneasy.
william said on 20 March 2011
@zecc – gee, what a contrary-mary.
Chris G said on 18 March 2011
Have you been through an earthquake. It is an interesting thing if you are not indoors. I had been through a mild quake (5.5) in AK and I was most interested in how it felt when the earth was moving. First, a rapid up and down motion that was short lived, followed by a longer duration slow swaying back and forth. It looks like in th video that the back and forth motion is what is being filmed. I am very impressed by the sturdiness of the Japanese structures. The tsunami seems to be the worse disaster.
Dave said on 18 March 2011
I have been through 3-4 earthquakes in California. They seem scarier when inside due to the noises caused by furniture, dishes, etc. I experiences while outside and they were not scary. Just the ground rolling back and forth.
paulie said on 30 March 2011
I live in California. Went through the (much smaller 1989 San Francisco quake). The Japanese aren’t drugged in the least! After a major event like that (and the huge adrenaline rush of terror it causes while it’s happening) I can assure you that it leaves people shocked and stunned. Freaking out is the last thing people do in the immediate aftermath of such an event.
ynw said on 18 March 2011
Very impressive! Any video about Christchurch?
Jude M said on 30 March 2011
Some interesting post-liquefaction video of a Christchurch suburb in this video here:
http://www.youtube.com/watch?v=F6-knLM7MZA
(set to a parody of ‘Fraction too much Friction’ by kiwi Tim Finn – quite appropriate…)
michael campbell said on 18 March 2011
It is remarkable video, but water spontaneously appearing is NOT liquefaction. Liquefaction may have been happening there, but the video did not show it. See: http://en.wikipedia.org/wiki/Earthquake_liquefaction
Christoph said on 18 March 2011
But we see the mud fountains, doesn’t that mean we see liquefied soil?
Garrett said on 18 March 2011
No. It is when soil acts like a liquid. Not when it mixed or replaced by a liquid. There are no liquids involved with liquefaction.
geology andy said on 19 March 2011
no liquid involved in liquefaction? ha wow that is the first time ive heard that. what do you think is the cause of soil acting like a liquid then?
David said on 21 March 2011
There is most definitely liquid involved in liquefaction. Liquefaction is the result of elevated ground water pressure caused by the sudden compression of loose cohesionless soil (sand), in this case resulting from earthquake shaking. When the water pressure becomes greater than the stress pushing the soil particles together (total overburden stress), the soil behaves as a liquid. No ground water = No liquification. The places where the water is coming out of the ground in the video are called sand boils and they are a classic symptom of liquefaction. The liquifaction itself is occurring below the ground. The sidewalk is basically floating on liquefied soil.
One Eye said on 19 March 2011
With the root word liquid primarily in the word, you’d think it would be a part of the process !
J Guffey said on 18 March 2011
I didn’t think it was liquefaction, but not an expert. When I watched it closely and turned up my volume, it sounded and appeared the ocean tides are having an effect on this area. The sounds reminded me of what I hear when at the beach. When the water squirts up out of the ground (toward the end of the video) then stops and starts over and over, seemed to me to be related to the tides.
P Ellis said on 18 March 2011
Michael Campbell: It’s subsurface liquefaction, with the water then being forced upwards though the surface layers. From the page you linked:
“The pressures generated during large earthquakes with many cycles of shaking can cause the liquefied sand and excess water to force its way to the ground surface from several metres below the ground. This is often observed as “sand boils” also called “sand blows” or “sand volcanoes” (as they appear to form small volcanic craters) at the ground surface.”
Leslie Hartten said on 18 March 2011
How do we know that it’s liquefaction and not subsurface pipes bursting (as suggested by the narration)?
Garrett said on 18 March 2011
Liquefaction is when soils become unstable and act like a liquid. Whether from pipes or groundwater, seeing water has nothing to do with liquefaction.
Leslie Hartten said on 18 March 2011
OK, I didn’t read all the comments closely enough — other people (including @Garrett) have noted that it’s a video of water, not of liquefaction. Maybe the post’s title needs a rewrite?
lmnop said on 18 March 2011
I’ll assume that most of the comments above are by geologists, and I’m one as well. Our reputation amongst the engineering professionals won’t be helped by comments such as “there are no liquids involved in liquefaction”. Really? Yikes…
Dayngr said on 18 March 2011
Truly amazing to witness. Thank you for sharing
Anthony said on 19 March 2011
Garrett is mostly wrong.
The soil some depth beneath the surface liquefied – loose saturated soil turned into a sand-water slurry. The dry ground above it cracked due to the loss of support and the earthquake shaking, and as the surface soil begins to settle, the liquefied soil is forced up through the cracks.
So you didn’t actually see the soil liquefy, but you did see its results, and you see liquefied soil coming up out of the ground. This looks a lot like the aftermath of the 1989 earthquake in San Francisco’s Marina District.
Philip said on 19 March 2011
In the Pacific Northwest USA we have extensive slackwater sediments left by multiple glacial flood events. They are shot full of clastic dikes, a concern b/c they can serve as preferential pathways for contaminants reaching groundwater. http://www.pnl.gov/main/publications/external/technical_reports/PNNL-14224.pdf. What we are seeing in the video is a likely mechanism for the formation of clastic dikes in sediments.
Januka said on 19 March 2011
Liquefaction without water and the next big one is on the “supermoon” day! great comic book stories ..
On a more serious note, Tokyo, where this is filmed, is about 150 miles Southwest of Sendai and hence the reduced but considerable shaking. The central park is within 10-15 miles of Tokyo Bay and on a possible alluvial fan, a prime candidate for liquefaction-prone area.
Brent Kooi said on 22 March 2011
I’m the person who shot this video. I didn’t think it was liquefaction at first as I assumed the surface would become liquefied. But reading these posts, it makes sense. I started shooting the video after the shaking stopped. I could not really feel the ground moving at this point. Days later, when the mud dried, it became obvious it was sand. It shot out of these cracks as the cracks contracted. And it did create miniature volcanoes — well, that’s what they looked like when everything dried — little mounds with a hole at the top. The beach (Tokyo Bay) is about 1 km away, so it is not the beach you hear. This was shot in Central Park of Makuhari, part of Chiba City, about 45 minutes east of Tokyo.
Bob Libra said on 22 March 2011
Brent excellent video! Are you the one who made it private?
Brent Kooi said on 27 March 2011
No – this is not my blog.
Solon Stewart said on 20 September 2011
Hi Brent, that was an excellent video that shows liquefaction in real time, something you rarely see. Can you put the video back up on YouTube (Since you shot it)? This is a great demonstration of the effects of liquefaction and can be used as a tool to teach people why this happens.
Solon Stewart said on 20 September 2011
Take it back. found it:
http://www.youtube.com/watch?v=rn3oAvmZY8k&feature=channel_video_title
Brent Kooi said on 20 September 2011
The video is on YouTube under my YT name: klompen222. It’s at:
http://www.youtube.com/watch?v=rn3oAvmZY8k
Lachlan Ward said on 23 March 2011
The video seems to be private now… is there anyway to watch it?
Cheers
Lachlan
Clyne said on 22 March 2011
Hey – I watched this video the other day and have been passing it around some friends to watch, but now it shows as private? Has it been pulled from youtube?
Private video said on 22 March 2011
Great blog. Sadly, this featured YouBoob video is now marked as ‘private’ and unwatchable. Should this blog article be redacted?
Bella said on 24 March 2011
It’s back on YouTube:
http://www.youtube.com/watch?v=b2f2Nw3j2fE
Brent Kooi said on 27 March 2011
A number of people have uploaded the CNN version on YouTube. The original is available at:
http://www.youtube.com/watch?v=rn3oAvmZY8k&feature=channel_video_title
Bella said on 30 March 2011
Thanks for making it available, Brent – and did you know it was featured on a BBC programme by Dr Iain Stewart about the earthquake that aired the other night? If you can access the BBC iPlayer it is viewable at http://www.bbc.co.uk/iplayer/episode/b0101nq2/Horizon_Japan_Earthquake_A_Horizon_Special_with_Iain_Stewart/
I can’t get over how cool you stayed throughtout!
Donna Goss said on 26 March 2011
I could not get the video but the description reminds me of something remarkable about liquefaction at Port Orford, OR. When I lived there, I took a walk along a 3 meter or so beach cliff with layers of unconsolidated sediments the ocean had eroded with winter storms. I found some faults in that with a fine sand filling going up through them. I also investigated a roadbank that a developer had recently cut a road through. There is was, a large sand dike going up through a fault some 6 meters high road to top of road cliff. AhAhAh! I thought of the magnitude of the earthquake that did it. The last great subduction earthquake of Cascadia was 1700, although it could have happened in a previous one, or during terrace uplift described by Harvey Kelsey. If I were doing geologic evaluations of properties, my report on that area would be very discouraging and real estate agents would not like me for scaring customers away.
Anthony said on 26 March 2011
Donna – it doesn’t take much of an earthquake to cause liquefaction, if the conditions are otherwise right. There was extensive liquefaction reported 100km from the epicenter of the 6.9 Loma Prieta earthquake in 1989. There aren’t that many 6.5+ earthquakes in the Pacific Northwest, but what you saw could be from any earthquake that size, even more recently than 1700.
California has rules about checking sites for liquefaction as part of doing a soils report before developing a property which require checking down to 50 feet in areas known to be susceptible to liquefaction.
O'Fla said on 8 May 2011
Thank you for putting this up, as the original link at the beginning goes to a video which apparently cannot be viewed anymore. This was fascinating!
Zan said on 18 July 2011
ALL of that can’t be liquefaction — it doesn’t make water rhythmically jet up out of the ground. it appears there may have been liquefaction in some areas, but it is clear in some parts of that video that the reclaimed land is moving in pulses, “floating” with the ocean that it was built on top of. it seems seawater has started bubbling up through the newly-made cracks.