A fraction liquefaction

11 comments on “A fraction liquefaction ”

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1. r0b 1

   2 April 2011 at 9:04 am

   Hate the original song. Love this parody! Plus, while most of the Chch imagery has been of fallen buildings, this really gives an idea of the liquefaction in the worst hit areas.
   • lprent 1.1

     2 April 2011 at 12:40 pm

     It is pretty good music. Great images of the subsidence potholing.
2. ianmac 2

   2 April 2011 at 10:09 am

   Sad for the people. What lies above ground be cleared with heartbreaking effort. But it is the spaces left underground from where the sand came, that must destroy the reality of rebuilding as well as the confidence of residents. Would I feel safe living there? And it shows the other side from the much shown Central city.
   • Armchair Critic 2.1

     2 April 2011 at 10:49 am

     Are there spaces underground where the liquifaction came from? I thought sand and water bubbled up and the soil above it collapsed into the holes, so most of the locations were known, and the potential for new holes in the ground was small.
     • lprent 2.1.1

       2 April 2011 at 12:10 pm

       No. Generally the liquid is held in suspension between soil / silt particles. This is pretty common amongst many types of sediments and soils. The most extreme example I know of this are the quick clays where the water content can be up to 80%.

       When the water gets shaken out of suspension, you will get a collapse of the solid soil structure with the water at top. It isn’t that the water rises to the top, it is the collapse of the interstitial soild structure that causes the water to appear at the top.

       You won’t get spaces forming underground except in very unusual circumstances – mostly where there is a slope and a slide
       • ianmac 2.1.1.1

         2 April 2011 at 12:34 pm

         I guess spaces is the wrong word. Just that the solids above the ground have to have come from somewhere so it must cause at least subsidence, but would the sub-soil then be consolidated enough to build on. Guess that will be a problem for the deciders. Help.
       • Lanthanide 2.1.1.2

         2 April 2011 at 1:28 pm

         The question is really what causes it to come up in humps and bumps? If you’ve got a perfectly flat road, and then there’s an earthquake and it domes up because of liquefaction underneath (very common, even on my side of town), where exactly did all that material come from? There’s not suddenly a hole in the ground where the sand and silt came from (in some places there is, but not all), so what’s taken the place of the sand and silt that bubbled up?
         • ianmac 2.1.1.2.1

           2 April 2011 at 3:01 pm

           That is my wonder too Lanthanide.
       • calltoaccount 2.1.1.3

         2 April 2011 at 1:57 pm

         Hmmm, there seems to be a lot of sand in that video Lynn.

         We’d like to think (some of those streets look a little too familiar to this Chcher) the holes are filled by more of the stuff off to the side, such as under Pegasus Bay. A bit like taking a handful out from the middle of a bucket of mud.

         But who knows? 🙁
3. RobC 3

   2 April 2011 at 10:11 am

   Yes, very clever!

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1. The Standard: posted on 1 April 2011 at 7:53 pm

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