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The Town That Creep Built (bldgblog.blogspot.com)
130 points by ascertain on May 7, 2015 | hide | past | favorite | 31 comments



How do property line disputes get resolved in an environment like this? Imagine you and your neighbor are engaged in a petty feud over the location of a block wall. Does your property change shape with the Earth? Or do fixed objects drift into your property, and now that wall belongs to you?

EDIT: This kind of answers, but it's not entirely clear: http://www.sfgate.com/bayarea/article/When-property-lines-ru...


I'm working with a simplified model - visualize a row of 10 houses, each on a square plot. There's a street running along the row of houses, and a street at each end.

Now, the land slides 1/2 plot to the right. To simplify this model, the slide happens overnight.

This means that each house slides right 1/2 plot. All of the cars slide 1/2 plot to the right. The yards and all the flowers slide 1/2 plot to the right.

And the road slides 1/2 plot to the right.

So this means that one of these residents now owns 1/2 plot of public roadway. Are they allowed to toll drivers for using their roadway?

The city (or county or state) now owns 1/2 plot of yard (and 1/2 of a house), which isn't quite as useful to them as the 1/2 plot of roadway they had before the shift.

Whichever governmental body that has authority could theoretically solve this by shifting all property lines to the right by 1/2 plot. This would line up the spots on the Earth's spherical surface (the land estate) with the objects held there by gravity and other forces (buildings and possessions).

---

Of course, the complicating force here is Human Boredom; since these changes happen over decades instead of a night, most people are not content to have the problem solved logically, as most people see problems as tools they can use as a reason to talk to other people.


Yeah, that case would be simple. But I'm thinking more about the plots that had half of their land move a couple feet, while the other half remains stationary.

    Before:                  After:
     --------o--------        --------o--------
    |        o        |      |        o        |
    | Hatfld o  McCoy |      | Hatfld o  McCoy |
    |        o        |         |        o        |
    |        o        |         |        o        |
     --------o--------           --------o--------

    (the o's are the block wall)

Do the McCoys now own half that wall? What if their house was in the top half of the property, and their driveway was along the western edge of the bottom half? Keeping old property shapes would allow them to re-pour a new driveway to line up with the garage, but first they have to demolish the the Hatfields' stupid wall.

BTW, this is gold:

> ...most people see problems as tools they can use as a reason to talk to other people.

I hope my choice of plot labels signals my agreement


But what happens if due to sliding, one house moves over 1/2 plot but after compression, the next property over moves over 1/4. Now a mathematical and spacial change based purely off of property lines is going to misrepresent the actual change, while an adjustment based off of sliding objects may strip someone of 1/4 a plot of land. It's not a simple "just move the plot" solution unfortunately.


Thanks for clarifying some of the details that complicate my simple model.

I feel like Eminent Domain might be one recourse - simply pay the land owner for the land that was lost. Though the land prices in California are so high as to make this prohibitively expensive.

Another solution could be to take that 1/2 plot of land the city got, and give 1/4 of that to the squeezed landowner. But that solution wouldn't scale well - I foresee a nightmare scenario where hundreds of people are trying to sell their fractional ownership of a sandlot, except for one disgruntled group member.


I think the answer to this scenario is simpler. Tell them, "Sorry, God just screwed you out of 1/4 of your land. Man that must suck. At least your property taxes will be reduced!"


Yes, but which god? Ishtar? Most of them aren't that fickle.


In the US, eminent domain is only allowed if the government pays a fair price for the land. What is a fair price for a partial plot that no longer exists?

Giving 1/4 of a plot of a different property probably isn't fair either. Different plots of the same size will often have different values, and having a bunch of tiny plots all over the place versus one normal-sized plot is not very useful.


This is why "Case law" is the dominant legal tradition. Human judgment is consulted.


This is an interesting photo:

http://4.bp.blogspot.com/-NqtW3VGYkuw/VGTYSD72MLI/AAAAAAAA_z...

It immediately makes you wonder what happens "underground"..


No need to wonder, sewer lines that cross a fault line simply break. During my time here in the SF Bay Area I know of at least three water line incidents which were directly caused by water mains that were damaged by earth movement. One in San Francisco in the late 90's created a huge sink hole as the water washed out the under part of a street, one in Berkeley where the REI store flooded, and one in Fremont which may have been a combination of fault motion and land settling.


Yes but they know the fault is exactly there and moving at a constant rate, it's possible they could plan for it.


That's really fascinating. I wonder how much a typical home can torque before it becomes unsafe and how would you go about fixing it? I can't imagine it's an easy repair. Can the house be lifted (as if it was going to be moved) and the foundation re-done or does it pretty much need to be demolished?


Jacking and lifting of houses are typically done when it's a relatively "static" issue that was improperly addressed when first built. For example, certain soils (mainly clays, very fine grained soils) compress and undergo consolidation (i.e. compress downwards) as a function of weight and time. Consolidation, when expected, can be mitigated and/or accelerated to "get it all out" so that there is no differential settlement in the future. For example, this here [1], looks to me like a case of differential settlement that resulted from improper excavation and back filling during original construction. In the case of fault-lines and stochastic motions? It's a lot harder to say what can or should be done in a general sense. Luckily the frames of most houses are made of wood, which has more forgiving properties (failing more with more ductility) than masonry. Unfortunately, the exterior shell of some houses are brick, which won't be so forgiving as the wood that it surrounds.

[1] https://www.reddit.com/r/DIY/comments/1dmt6l/advice_for_jack...


It's not just the houses - think about the water, sewer, and gas lines buried under the roads. Overhead electric service at least has some slack in the wires, so it'll be OK for a while...


If the house is a frame house on pilings, it's pretty easy to fix that way; if it's a monolithic slab, block home, you're screwed. So it depends heavily on the foundation and construction style.


And I imagine if, at this point, you're not constructing houses with this activity in mind, there's no one to blame but yourself. Sure, it sucks for older houses, but if newer houses are being built more commonly now as the article says, the problem should go away over time.


I can't help but look at the roads and sidewalks and think there's a solution that could be implemented there. I'm no engineer, but I expect that you could install something along the fault line that allows the road to slide apart without disruption. It seems like a waste to just keep repaving the same spot over and over, just for it to crack again.

Maybe tear up a couple feet of pavement and put in two metal grates that can slide past each other. That should at least buy you a decent amount of time, until the road is so warped that the lanes don't line up.


The Alyeska pipeline in Alaska is built on rails just like this over the parts near the Denali Fault.

http://earthquake.usgs.gov/earthquakes/eqarchives/year/2002/...


I stared at that for far too long, waiting for the animation to start.


This was one of my thoughts as well; as a software developer I'm always trying to figure out solutions to problems but I know just about nothing when it comes to civil engineering. So naturally I keep coming up with crazy ideas to prevent / fix this and none of them are probably feasible :)

But it's certainly interesting to review stuff on the internet about how structures can avoid these issues.


So what happens to the underground infrastructure? Water, sewage, storm-drains, gas?


Do homeowner's insurance policies out in California cover ground movement?


As a surprising aside, I found that homeowner's insurance in Hawaii covers "destruction of house due to lava" but not "destruction of the entire area around house, but not house due to lava".

There are people who have no roads, water, sewer or electric because their house was turned into an island by lava flows - and they have no recourse to do anything with their property (that they sometimes cannot even get to any more).


If the lava flow is active, built a drawbridge and have the best moat ever!


underfloor heating included if you're lucky, though that may be of little appeal given the climate.


Seems like a good reason to build your house in a slight valley. That way if the lava comes, you can be reasonably sure it will take out your house.

Although perhaps the insurance companies would not like that trick.


They typically do not include earthquakes, but I'm not sure about super slow movement like this. I'd bet "no", though.


I would guess not. They probably use the generic "earth movement" phrase, either natural or man-made, to exclude coverage.

http://geology.com/articles/homeowners-insurance/policy-what...


One of my favorite nearby parks: http://www.yelp.com/biz/los-trancos-open-space-preserve-palo... has the San Andreas fault going right through it. You can see where the fence line has been deformed by creep.

On the plus side if it deforms you don't get a lot of energy buildup.


reminded about what happens to buildings built on permafrost in Siberia on shoddy quality foundations (i.e. for example the correct foundation should go well deeper than summer thaw depth)




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