How much should I worry about earthquakes in Seattle?

July 6, 2006 8:23 PM

How much should I worry about earthquakes when looking at apartments in Seattle?

I'm looking for a new apartment in Seattle and I far prefer the older buildings to the newer ones, which cost more and tend to include ridiculous amenities I will never use. However, I'm mildly concerned because bad things happen to unreinforced brick buildings in earthquakes.

How much protection do I get from the fact that the Juan de Fuca is ~200 miles away from the city? I was in a 7-pointer in LA that happened maybe 150 miles away from the city and the shaking was hard enough to wake most of the dorm up. The Juan de Fuca produces infrequent 9-pointers. Should I even bother worrying about something that happens every 600 years or so (on average) and would probably destroy a lot of the new construction right along with the old?

What about smaller-but-closer quakes that happen on other faults? Obviously none of the buildings I'm looking at collapsed in the 6.8 they had a few years back. That one was some distance from Seattle but caused damage to unreinforced masonry buildings in Pioneer Square.

I've read through this related question.

posted by clarahamster to Science & Nature (13 answers total)

None. Get rental/homeowners insurance and live wherever you like.

Uh, so as someone born and raised in California, along some of the worst faultlines on the West Coast, I would say don't sweat the small stuff, and earthquakes are pretty small. (As for that picture, that quake was a 7.5 only 2 miles off the coast of San Fransisco, not 200 miles away).

Become an earthquake junky. Live for this site.
posted by muddgirl at 8:44 PM on July 6, 2006

Sorry, the 1906 San Fran quake was somewhere between a 7.7 to an 8.3.

Also, asking the building owner about Earthquake safety might be a good idea - there are codes and such for this stuff now.
posted by muddgirl at 8:46 PM on July 6, 2006

Uh, so as someone born and raised in California, along some of the worst faultlines on the West Coast, I would say don't sweat the small stuff, and earthquakes are pretty small.

Yeah, i didn't worry so much about them in CA, but they had better building codes for the new construction and went back and reinforced a lot of the old construction.
posted by clarahamster at 8:47 PM on July 6, 2006

There's a ton of new construction in Belltown that has got to be built to the new codes. Look there. I was there for the 6.8 and saw what happened to Pioneer Square first hand. Scary stuff.
posted by photoslob at 9:07 PM on July 6, 2006

How much protection do I get from the fact that the Juan de Fuca is ~200 miles away from the city? I was in a 7-pointer in LA that happened maybe 150 miles away from the city and the shaking was hard enough to wake most of the dorm up.

Distance and scales are only parts of the equation. You have to consider the type of faults, the types of construction, the geology of the surrounding area, etc. After all, even a 1.0 can kill you ... if it knocks something heavy off a shelf that hits you in the head.

There's really nothing you can do to completely avoid an earthquake in the Seattle area. All you can do is minimize your risk.

* Stay away from older construction.
* Stay away from older construction nearby.
* Stay away from areas known for loose, sandy soils (e.g. Pioneer Square, waterfront areas, etc).
* Stay away from possible landslide areas (e.g. under or on a cliff, ravine, hillside, etc).
* Stay away from watershed areas or areas that could be prone to flooding.

Pioneer Square = bad
Top of Capitol Hill = better
Top of West Seattle = better
Alki Beach = bad
Wallingford = better
UDistrict = most areas good
Ballard = bad in some areas

And then ... have a fire extinguisher, water bottles, first aid kits, etc.
posted by frogan at 9:53 PM on July 6, 2006

Seattle's soils are very nonuniform, and this has a huge effect on how an earthquake will affect any given spot. Most of the area is glacial till: stuff that was dropped by a glacier and then sat on by another glacier for a zillion years. There's one place, on Capitol Hill, where the bedrock comes near the surface. And most of the downtown waterfront is fill, either from the Denny regrade or fill projects over the years.

Things to stay away from are fill areas, steep hills that have been built up enough that they might liquefy, and brick construction. (Old wood construction is, as far as I know, fine, but I don't know how many apartment buildings you'd find like that.)

You can get more information than you'll ever use by going to the downtown public library and asking. The city maintains a lot of public information on earthquake and rain hazards like this. Last time I looked it up, they had GIS terminals there for your use; it might all be online these days.
posted by hattifattener at 10:30 PM on July 6, 2006

I'll definitely agree with avoiding brick construction, I lived on First Hill at the time & a brick building that wasn't all that old across the street had a partial collapse. Every time I left town there was a disaster: earthquake, WTO riots, massive blizzard. It got so my coworkers were afraid to send me away.
posted by scalefree at 11:12 PM on July 6, 2006

The Juan de Fuca produces infrequent 9-pointers.

The key here is infrequent. If it were to happen as it did in 1700, it wouldn't matter where you lived, because you would likely be dead. The 1700 quake raised the marshland that became the Stadium/Sodo area as much as 10 feet.

And the other major hazard, the Seattle Fault, would be just about as deadly. It's crustal and slices right through the residential heart of south Seattle.

I'd listen to what everyone else has said. Avoid liquefaction and slide zones. Here's a map of them (in glorious PDF). And here's the city's website on quakes.

Avoid brick, but that shouldn't be hard. The hilltops don't have a history of quake damage. While Sodo was hit hard, Capitol Hill and Queen Anne had minimal damage. The length of Phinney Ridge had some toppled chimneys, but that was the extent of the damage.
posted by dw at 12:02 AM on July 7, 2006

Capitol Hill and Queen Anne had minimal damage

So do the apparently-brick apartment buildings on Capitol Hill just have brick facades on sturdier structures, or have they just avoided damage so far because they're in better locations?
posted by clarahamster at 12:44 AM on July 7, 2006

I was in Cap. Hill during the "big one" in '01, down the hill and very close to I-5, and my rather old brick apartment building shook like a mother. Just next door, in a newer apartment building, my friend said he barely felt it. Kind of a crapshoot, but new is good.
posted by zardoz at 1:21 AM on July 7, 2006

Most of downtown Seattle has had some fill work and/or regrading in the last hundred years. So strictly speaking, that will impact earthquake safety. Yes, Pioneer Square had a problem with brick fascades collapsing, but it is worth noting that Pioneer Square is also where they run the Underground tour. That means that as you are walking on the street, there is another set of sidewalks ten feet below you, and the shops at "ground level" were once second floor. (I say this for the benefit of those who don't know, please forgive me if you are thinking "Duh!"). In short, how much of the problem down there was the brickwork, and how much of the problem was the regrade?

DW and Frogan both said good things, and you should absolutely ask leasing agents about building codes and retrofits as far as earthquake safety, however I am wondering something. When you say "in Seattle," do you really want to live in town? What about the Eastside? If you are willing to consider Snohomish County (Bothell, Lynnwood, etc) you have greatly reduced rates for earthquake insurance. So the actuaries must think Snohomish County has a greatly reduced risk of damage in an earthquake, the way I see it. The trade off of course is that if you work in town, you will be yet another person on I-5 or 99. At least the busses seem to have sensible routes.
posted by ilsa at 9:17 AM on July 7, 2006

Man, I love my Seattle brick house. It's made it through 100 years of quakes, I'm counting on it to get me through a few more.
posted by GaelFC at 10:47 AM on July 7, 2006

When you say "in Seattle," do you really want to live in town?

Right now, I'm mostly looking in the Capitol Hill area, which sounds like it's decently safe soil-wise if I can just find a reasonably new building that I like.
posted by clarahamster at 5:25 PM on July 7, 2006