Liquefaction in a barrow

By Grant Jacobs 02/03/2011 21


Liquefaction has been a major effect of the two large earthquakes at Christchurch over the past 6 months (Sep. 4th, 2010 and Feb. 22nd 2011). Here’s a clever little video illustrating liquefaction in a wheel barrow that’s gathered over 35,000 hits at the time of writing:

Update: My thanks to reader ‘Ross’ who brought this to my attention.

(Updated 6th March to add tags.)


Other articles in Code for life:

Lyttelton earthquake peak ground acceleration

On learning the sounds of a new (spoken) language

Beautiful peaceful images

On alternatives to academic careers and “letting go”

Deleting a gene can turn an ovary into a testis in adult mammals


21 Responses to “Liquefaction in a barrow”

  • When I was clearing up some of the liqifaction silt after a week of it being on the ground I noticed the weed growth around it was particularly lush. It would be interesting to know how nutrient rich this material is. In our area, it is unlikely it was contaminated with sewage which makes me wonder whether it would be worth mixing it into the garden.

  • I can’t help you with that one, but good question – anyone?

    (Naïvely) I wouldn’t have thought it’d have that much organic content if it comes from more that a few centimetres under the top soil, but perhaps it’s rich in minerals?

    You’re a chemist, aren’t you? Perhaps you need to take a sample to the lab… 😉

    (I’m kidding: your labs will be inside the cordon I know, and almost certainly a mess. How do you clean up a chemistry lab that’s be trashed by an earthquake? Perhaps there’s a blog post there – ?)

  • Actually, I’ve already taken a sample and put it aside :-)
    Don’t know when I will get access to our labs again. They survived the last earthquake quite well, so fingers crossed. Our technicians secure the labs very thoroughly.
    The biggest challenge at the moment is our server has gone down eliminating usual contact method for staff. However, via phone, facebook and other media we have gradually established contact with most staff.

  • Actually, I’ve already taken a sample and put it aside :-)

    Honestly, I should have thought you’d do that. I hope you write us a post with your analysis 😉

  • Gosh that’s a great little video! Sort of like when you stand down on the wet sand, just above the water, & paddle your feet up & down – you end up in a pool of water with your feet rather further down than they started!

  • Alison,

    Gosh that’s a great little video!

    It is isn’t?

    I wonder if your example might be a simplified version of what happens to some buildings? (We need a geologist around here; they’ll all be pretty busy right now.)

    Your example brings back memories, too :-) We where all little kids who stomped on the wet sand.

  • Thank you for this. I have posted it to my FB page as those beyond Christchurch continue to understand the challenges you all face. Best wishes our thoughts are with you.

  • Michael,

    Anything to report from your drive?

    There’s this on today’s NZ Herald daily rolling update:

    “9.18am
    Gerry Brownlee says he did not realise how neglected the eastern suburbs of Christchurch have been.
    There have been complaints from residents that they are being ignored and have no portaloos.
    The Earthquake Recovery Minister says his focus today will be to remedy that.”

  • Thanks Pauline, your help is greatly appreciated.

    Grant, my drive yesterday was both saddening and heartening. With wind gusts the silt produced awful gritty clouds across the areas of the city worst affected by liquifaction. In the midst of that were student and other volunteers wearing masks and tryingto remove the stuff. Students may get a bad rap for their antics around orientation, but what they are doing is phenomenal.
    At the distribution centre, there were lots of helpers working hard in the grit to distribute food and water.
    Council and private roading companies are out in force getting repairs made to the roads, particularly around bridges where the some roads have dropped about half a foot (or perhaps the bridges rose, its hard to tell). Power company vans are everywhere trying to get the power systems up and running.
    Looking at the building on my travels I have vowed never to build with brick or roof tiles. Many tile roofs have gaps in them and some look like the whole roof has been shaken until they are all out of place. There are buildings with huge cracks in them and the roads – cracked, with bulges in the middle of them that make driving difficult. Other have large potholes. I wouldn’t want to be driving at night in Christchurch for a while.
    Despite the physical damage I am so proud of the many acts of generosity I have seen and heard of. With many cars trapped in the central city, some people are ferrying those without cars around the city. Others are taking care of elderly neighbours, those with scared children etc. Those with power and water are offering showers, use of washing machines, charging cellphones, food, water and rooms to those who don’t have them.
    At least today it is a sunny day with only a little wind so no great clouds of grit.

  • Thanks for the reportage from “the front” 😉

    It’s pretty much what I imagined. (I’ve relatives who live in that general direction and have passed through the area after the Sep. 4th event, which gives a little of a feel of what to expect – ?)

  • “petersmith” — “Ron” in drag* :

    I am not approving comments from you at this time owing to your spectacular rudeness over recent days, which in large part ruined another discussion on these forums. I try hard to encourage a decent tone of conversation on my blog. You, by contrast, have repeatedly disrupted a number of discussions with personal attacks.

    * He has posted under several different names.

  • Alison – I once proof read a geotechnical engineer’s masters thesis on post-earthquake liquefaction, and that beach example is exactly how he explained it to me.

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