March 11, 2011
Liquefaction in an aftershock
Posted by Austin Elliott
I stumbled upon a fascinating video a couple of weeks ago showing what happens to sand volcanoes as seismic waves pass. This would have fit in either my aftershocks or my liquefaction posts from last week, but it’s both stunning and unique so I decided it deserves a post of its own.
http://www.youtube.com/watch?v=Nv–8ybjnwk
This New Zealand man is filming sand blows forming from liquefaction of a school yard in the 22 Feb M6.3 earthquake, when a large aftershock hits. Shaking from the aftershock isn’t immediately visibly apparent, but shrieks and metallic rattling herald its onset. Once the sharp noisy shaking is over, the ground continues undulating, apparent only in the fissures opened from liquefaction. As the seismic waves from the aftershock compress, dilate, and otherwise jostle the ground, the fissures feeding the sand blows open and close, alternately squirting silty water out and drawing it back down–along with the air above.
Quite a phenomenal illustration of the ground’s undulation. The sight of this lends credence to some alleged eye-witness reports of the 1811-1812 Missouri earthquakes, which claim that as the ground heaved, “fissures opened and slammed shut… spewing water high into the air.” Reports like this (especially from random websites) tend to suffer from the telephone syndrome, in which subtle modifications by a series of reporters lead to misinformation. So take the accounts in that link with a grain of salt; perhaps I’ll compile legitimate resources on that fascinating earthquake sequence in a future post.
Hello,
I was browsing the topic of liquefaction during aftershocks, when I found your post. The video is not opening, is it still online?
Unfortunately, no, the existing link appears to be broken, and I haven’t been able to find any other version of this video posted. It appears the original has been taken down and simply not put back up–it’s particularly unfortunate that it’s left no trace of authorship, content, etc.
I stumbled on to this post just the other day and was sad about the broken link as well. I typed “sand volcano new zealand” into youtube and found these from user “boxter1977”. He mentions filming at a school so I’m hopeful I’ve rediscovered something interesting.
https://www.youtube.com/watch?v=zuYVnm5AXVs
https://www.youtube.com/watch?v=UbvCKzR34Ko
https://www.youtube.com/watch?v=zUBVGpjzJ64
https://www.youtube.com/watch?v=BkRF110n98k
Oh wow, great sleuthing! That does look pretty much like the setting of the other one, if I’m remembering correctly… those these aren’t it, as they don’t show the large aftershock happening. Nonetheless a great collection of videos! I’m hoping somehow eventually we can track down the original posted here.