anyGEOLOGIST's guess?SINKING subdivision,lakeport,CA

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neebee

Social climber
calif/texas
Topic Author's Original Post - May 12, 2013 - 12:22am PT
hey there say, all... seems this is in a volcanic area of the past:


any of you climbers in calif, know this subdivison area, or know folks that live near here??

just curious, also, and geologists, etc, here, have any ideas
on this...

http://news.yahoo.com/one-one-homes-calif-subdivision-sinking-162144171.html

sure feel bad for the families, but thankfully, they have had a chance to get out, and no houses fell through the night, :O
neebee

Social climber
calif/texas
Topic Author's Reply - May 13, 2013 - 05:54am PT
hey there all, say... just a bump...
was still a bit curious...


:)
Jan

Mountain climber
Okinawa, Japan
May 13, 2013 - 06:49am PT
From what I've read, that area was full of geyers and hot springs until the turn of the 20th century when they all went dry. Now the cause of the sinking is ground water that they don't know the source of. So far it isn't hot water, but clearly something has changed underground and diverted it from somewhere.
Donny... the OHHH!- Riginal

Sport climber
C:porn
May 13, 2013 - 12:25pm PT
I'm plumb sure gots somethin' t'do with them there homosechulz.
Reilly

Mountain climber
The Other Monrovia- CA
May 13, 2013 - 12:32pm PT
People get so surprised when geologic time coincides with people time.
I would be saddened too but not surprised. I've already had to rebuild my
house once thanks to 'geology'. The real issue is how the insurance companies
will try to sleaze their way out of compensating them.
ydpl8s

Trad climber
Santa Monica, California
May 13, 2013 - 12:52pm PT
Whenever you have water going into or out of an area that it has either been before, or not, there will be structural compensation going on as the water and the rocks find their new equilibrium. If the water is periodically recharging and draining, the "compensation" will be even more pronounced.
mechrist

Gym climber
South of Heaven
May 13, 2013 - 12:57pm PT
It is a bit surprising for a couple of reasons: 1) they have apparently been there for at least 11 years, many of which were wetter than this year, with apparently no settling, 2) the homes are on a "hilltop" where groundwater levels would be expected to drop the most during dry years.

Here is a map of seismic activity from the end of the last wet season (June 2012) to the end of March 2013, when movement apparently began. Most of the seismic activity is south of Clear Lake (near Cobb), but the homes/slide are reported to be "north of Lakeport." If the change in groundwater were associated with those quakes, I would expect them to also affect the level of Clear Lake... which was not appreciably higher.


Activities higher or lower in the watershed, such as clear cutting, changes in lake levels, new reservoirs, higher lake levels, etc could definitely cause changes in the water table, which the article insinuates is leading to the slides.

It could also be the result of over pumping of groundwater, which would reduce the pore pressure and lead to subsidence. But that usually occurs over a longer period of time, at least in sedimentary systems. This being volcanic rock, with plenty of large voids, I suppose a sufficient drop in groundwater levels COULD lead to subterranean mass wasting/collapse.

It would help to know exactly where those homes were... post up if anyone sees an address, street name, etc.
Some Random Guy

climber
Under a Little Pink Umbrella
May 13, 2013 - 01:09pm PT
But they're so perplexed they also talk about the land being haunted and are considering asking the local Native American tribe if the hilltop was an ancient graveyard.
"Someone said it must be hexed," said Blanka Doren, a 72-year-old German immigrant...
my bet is either that or something related to all those damn tweakers up there.

....indian tweaker zombies.....
geo_nutt

Gym climber
the big bang
May 13, 2013 - 01:58pm PT
considering science is part of the left wing agenda corrupting the minds of our youths today... better leave the geologist out of it... not to mention they are just a bunch of freeloaders living off of taxpayers money sitting around campfires drinking beer and smoking skunk weed. Trust me listen to a geologist and the next thing you know they will having you believe the earth is billions of years old and that we are an insignificant speck in the universe which of course implies that gay marriage is ok which if we allow gays to marry why not allow people to marry monkeys - which of course I think is awesome! As I have always wanted to get down and busy with a monkey, I mean have you seen the butts on those things! Which is of course why I became a geologist... to corrupt your mind so I can have sex with monkeys... that said I haven't a clue why the ground is subsiding, probably too much time drinking beer and smoking skunk all the while dreaming of monkeys, that said it wouldn't surprise me if fluids in the ground played a role somehow... who knows maybe its a creeping fault... that would be kind of cool... but probably not likely. That it is volcanics is interesting, how high is the porosity and permeability? What else is going on in the region? Any springs? Any with hot water? if so have there been any recent changes in flow or perhaps temperature?

who am I kidding just read the bible the answer should be in there somewhere...
TwistedCrank

climber
Dingleberry Gulch, Ideeho
May 13, 2013 - 02:02pm PT
Triffids
squishy

Mountain climber
May 13, 2013 - 02:29pm PT
oh geonut, you make me wanna become a monkey..
mechrist

Gym climber
South of Heaven
May 13, 2013 - 03:18pm PT
squishy geo_nutt monkey love

The name of my next boulder problem? Perhaps...
mechrist

Gym climber
South of Heaven
May 13, 2013 - 04:32pm PT
and if you had a sense of humor... you'd probably be funny
Gary

Social climber
Desolation Basin, Calif.
May 13, 2013 - 04:36pm PT
Some developer skimped on the geotech, or falsified a geotech report. Happens more often than you'd think..
Reilly

Mountain climber
The Other Monrovia- CA
May 13, 2013 - 04:47pm PT
Yeah, and they were pretty remiss in building Anchorage where they did... ;-)
It did make it easy to get out of the second stories on 4th St.

Jan

Mountain climber
Okinawa, Japan
May 13, 2013 - 09:55pm PT
That's interesting because the article I saw said they had found a couple of small leaks in the sewer line but they couldn't have been responsible for such extensive damage. I guess that statement was just damage control.
rottingjohnny

Sport climber
mammoth lakes ca
May 13, 2013 - 09:58pm PT
Dumb isn't funny....Life is serious....Americans are stupid....
labrat

Trad climber
Auburn, CA
May 13, 2013 - 10:06pm PT
The story above is 26th of March. The OP story is 11th of May. It looks to me as they initially though it was leaky pipes and they were only a symptoms of a much bigger problem. I think it's too big to be caused by leaky pipes at this point.

My sympathies to the home owners. Really sucks ;-(
mechrist

Gym climber
South of Heaven
May 13, 2013 - 10:07pm PT
The first response to any of life's questions should always be...

Good god man call a geologist!!!11111
labrat

Trad climber
Auburn, CA
May 13, 2013 - 10:12pm PT
Or a geotech

http://en.wikipedia.org/wiki/Geotechnical_engineering

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