The '89 earthquake in San Francisco/Oakland caused some liquifaction in the parts of the city built on fill in the bay. I remember seeing photos of the 3 story houses tipping and sinking into the ground. It is no trivial matter. Regards, Bob S.
On Tue, Feb 22, 2011 at 8:52 PM, David Mann <[email protected]> wrote: > 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. > -- 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.
