On Feb 23, 2011, at 2:16 PM, Tanya Love wrote: > Shit Dave, are you guys ok? It is horrible to watch, I am glued to the tv, > and have abc news streaming on my second monitor as I am sitting here > working. > > Can you explain what the deal is with liquefaction? It looks like an > amazing phenomenon I have seen it all over the media and never heard of it > before now...
Yep we're fine. Our house is fine, just some minor damage and a bit of a mess. Nearly all of the footage you're seeing is likely to be from the CBD which is by far the worst affected area. I agree that it's horrible to watch, I haven't been watching the TV much but I've had the radio on quite a lot. I'm no geologist but... liquefaction is where shaking causes the soil to behave much like a liquid. Because of that, buildings can start to sink as the ground suddenly has a much lower density. Water streams out from cracks in the ground and carries quite a lot of silt with it. The water actually kept flowing for a couple of hours after the shaking stopped, as the ground settled down again. This city is built on low-lying flat land which was previously a swamp, and there are many aquifers running through it. So the presence of all that water makes the soil very prone to liquefaction in many places. If you feel like reading a textbook explanation... http://en.wikipedia.org/wiki/Soil_liquefaction Cheers, Dave -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
