Safety and maintenance of basement apartment in Northern California?
March 24, 2014 9:26 PM   Subscribe

I am considering living in a basement apartment near a major fault line. Is this safe?

The apartment is in a three unit, two story, ca. 1910 Victorian located in Northern California. The walkway slopes down to meet the unit's sole door. All of the rooms are about five feet down, with windows peeking up a few feet above-ground throughout. The unit has flooded in the past, but is now covered by redundant sump pumps. Most resources about basement earthquake safety focus on soft-floor construction, which I'm pretty sure this is not, so I'm at a loss.

Is it safe? Is there anything I should double check before signing?
I'd love to see any references you can find!
posted by nilihm to Home & Garden (13 answers total)
Response by poster: Actually, it is very clearly not a Victorian. My mistake. I'd be grateful for an edit, here, but a comment will do fine.
posted by nilihm at 9:29 PM on March 24, 2014

I wouldn't do it, I'd be worried about soil liquefaction bringing the whole house on top of me. For an extreme example, see the Valencia Hotel in the 1906 earthquake in SF.
posted by bottlebrushtree at 10:13 PM on March 24, 2014 [2 favorites]

We can't know with this information, because presumably some retrofitting has occurred in the past century. For example, are the foundation and stem wall concrete or brick? (Brick is more likely to collapse into a heavy pile during an earthquake.) All the sump pump retrofitting might have included a foundation replacement. I'd ask what kind of earthquake retrofitting has occurred.
posted by slidell at 10:21 PM on March 24, 2014

I'm from NYC and live in LA now. I was alive and paying attention through two major quakes in California (Northridge in 1994, and the earthquake that collapsed part of the Bay Bridge in 1989...)

I know there is some kind of reinforcing that is done to houses and apartment - I do not know if it really works, or if it fails at a certain magnitude of earthquake.

I would not live in a basement in earthquake territory. I also lived in Wellington, NZ, where the national museum is built on "shock absorber" type things to protect from earthquakes.

Find something else. Don't roll the dice. You will never feel safe or comfortable.

You live in California. We already live on edge about earthquakes as it is. Why add to the daily drama?
posted by jbenben at 10:22 PM on March 24, 2014 [1 favorite]

Here is the information requested by slidell:

The sump pump installation was as simple as possible.

"This structure has had some additional seismic upgrading to the perimeter foundation wall system and associated cripple wall seismic bracing."

"Above grade concrete raised foundation. Framing consists of above grade cement piers, wood posts, wood beams and wood floor joist.
posted by nominal at 10:29 PM on March 24, 2014

Liquefaction isn't something that just happens. If the house is built on landfill or poor soils, then yes, that would be a concern. BUT, if this a 100 year old house on a faultline, that likely would have happened already.

If it's something that's going to cause you distress, whether justified or not, you probably shouldn't do it. I personally wouldn't have a problem with it, and you're not necessarily going to find something "safer" - you'll just feel safer because you don't know where the closest fault line is.

Soft stories are generally where there's a heavy structure built directly on top of a lighter one. The canonical example is an office building with a really open ground floor built on columns, but with more solid upper floors that have a lot of partition walls and other load. Once the earth starts moving, all that weight acts like an upside down pendulum and is too much for the open first floor to resist. A two or three story apartment building or house isn't going to have that issue.
posted by LionIndex at 10:30 PM on March 24, 2014 [1 favorite]

Forgot to mention: my first concern in a basement apartment would be that there are two means of egress that you can use. Technically, your apartment is required to have at least two, but given the age, the windows may not meet current requirements. Make sure that you'd be able to climb out of one of the windows if you had to - not necessarily just because of earthquakes, but also in case a fire prevents you from using the main exit. You should be able to easily get through the window and then out from the building to open ground - if the window is too deep underground to allow that, there should be "window wells" - little retaining wall areas just outside the window that'll give you about a 3'x3' area.
posted by LionIndex at 10:35 PM on March 24, 2014

If you're in a building that collapsed, I'm not sure that being on the first or third floor would be a whole lot better than being in the basement.

Where it's built is pretty important. In the off chance that we're talking about San Francisco (which has a ton of Edwardian buildings built not long after 1906) a good rule of thumb is if it's somewhere flat, it's a liquefaction zone, and if it's somewhere hilly it's not. USGS has some detailed liquefaction maps for some other parts of the Bay Area, and possibly other regions too though I haven't looked for those so *shrug*.
posted by aubilenon at 12:05 AM on March 25, 2014 [1 favorite]

If there is a storm and the power fails, so will the sump pumps. Also, the sump has open water in it, no cover = kind of icky and attractive to who knows what kind of vermin seeking water. Not for me, but you may be braver.
posted by Cranberry at 1:29 AM on March 25, 2014

If it's 100 years old and hasn't fallen down yet, why do you think it will now? It's not as if earthquakes are a rare occurrence in northern CA.
posted by empath at 2:48 AM on March 25, 2014 [1 favorite]

I'd be more concerned with mold. Unless this is an amazingly cheap apartment in a fabulous neighborhood, I'd keep looking.

The sump pumps turn me right off.
posted by Ruthless Bunny at 5:20 AM on March 25, 2014

Nthing the mold issue and no sunlight. The two major eq's I have been through, water saturated areas sustained significant damage, both in LA and the Loma Prieta quake.
posted by effluvia at 6:10 AM on March 25, 2014

Liquefaction is still (!) poorly understood, but my best understanding is that it tends to be site-specific and is often connected to fill or other loose soil situation.

Personally, I'd be more concerned about living near the fault line itself than anything dependent on being in the basement itself. Very few earthquakes (really) actually collapse buildings, but many of them are strong enough to shake furniture around, topple bookshelves and television sets, and other issues that can lead to injury, not to mention problems with gas lines and the like, which can cause secondary fires and explosions.

FEMA sez:
According to the Federal Emergency Management Agency, most earthquake injuries occur "when people inside buildings attempt to move to a different location inside the building or try to leave." Thus, if you're inside your basement when an earthquake hits, by all means, stay there.

It may seem that you're at greater risk under parts of a building, but paradoxically you're also protected by the structure, which in most earthquakes won't actually be splintered to kindling but will stay together and move as a unit even if it's stressed or offset by ground movement. Moving around outside in an urban environment means you're vulnerable to walls or roofs or fire escapes or telephone poles falling unpredictably around you -- and with no structure to protect you whatsoever.

It's also not clear what you mean by "Northern California" here. To some that's the northern half from around Fresno on up, to others it doesn't begin until the Bay Area, and to others yet it's all the way north. If you mean you're near one of the ancillary San Andreas faults, that's one thing, but lots of "Northern California" however you define it is pretty far away from active fault lines. Even ones considered active may have seen little activity that could damage structure in years. Yet despite this millions of people live in and around these fault lines and -- fortunately, perhaps -- recent significant quakes have had very low death or injury rates.

You will never feel safe or comfortable.

Well, this is the kicker. Because you want to feel safe and if you don't, well, you don't.
posted by dhartung at 12:13 PM on March 25, 2014

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