In California, many buildings remain vulnerable to earthquake damage

February 15, 20235:42 PM ET
Heard on All Things Considered

AILSA CHANGTwitter

Transcript

NPR's Ailsa Chang talks with LAist News reporter Jacob Margolis about how many buildings in California are still susceptible to earthquake damage.

AILSA CHANG, HOST:

After the devastating earthquakes in Turkey and Syria, many of the people who died or were severely injured were trapped under the rubble of collapsed buildings. A number of those structures were built a long time ago, and even some of the more recently built ones were not up to code - factors that experts say likely contributed to the soaring death toll. The disaster in Turkey and Syria has triggered concerns in other disaster-prone areas of the world, including here in the U.S.

Jacob Margolis is a reporter for LAist news, and he's here to tell us more about why California, especially, is on alert. Hey, Jacob.

JACOB MARGOLIS, BYLINE: Hey.

CHANG: OK. So before we talk about the problems facing us here in California, what is it about the construction of many of these buildings in Turkey and Syria that collapsed that experts think made those buildings especially vulnerable to earthquake damage?

MARGOLIS: Yeah. It seems that many of the buildings that collapsed were concrete structures that didn't have adequate reinforcement to help them deal with ground motions that were really extreme. We're talking a velocity of - I think it's about three feet a second, which is huge. It's still being investigated, but it will likely be found that some of the structures, they didn't have proper rebar or concrete or even wall-to-floor connections so that when the ground moved that violently, columns collapsed, and then there's nothing holding the big, heavy floors up. And then the rest of the building comes down following it.

Now, like, I want to note - and people should note - Turkey has building codes on par with California and Japan, according to different engineers that I've spoken with. So the question is, like, why did the buildings collapse? And that's all being sorted. I know there's a delegation of engineers heading over to do some assessments, including from the U.S., and we'll learn more once things settle down.

CHANG: Right. But do you have a sense right now of how common those structural vulnerabilities that you've described in concrete buildings in Turkey and Syria - how common those are in California buildings?

MARGOLIS: Yeah. We have a lot of concrete buildings here in California that we know could very well collapse in a big earthquake. Anyone who thinks it's not going to happen or that it couldn't happen is delusional. I mean, we have, for instance, in Los Angeles, a program that is specifically meant for a type of concrete building built prior to the late 1970s that is saying, hey, you need to retrofit these buildings. But the timeline is like 25-plus years probably. Just to put it in perspective, there's a 15% chance that we're going to get hit here in Southern California with a 7.8 magnitude or greater quake sometime in the next 30 years.

CHANG: Right.

MARGOLIS: And so we have a lower concentration of those types of concrete buildings here. And that's one thing that we actually have working for us is that we've got a lot of sprawl, especially here in Southern California, where I am - a lot of single-family, wood-frame homes. And those do pretty well in earthquakes, and they're much easier to retrofit than the big, concrete buildings as well.

CHANG: Well, if experts know that there are these deeply concerning structural weaknesses in so many buildings in California and we are expecting the so-called big one someday here in the state, why haven't these buildings been brought up to code? Like, why are they given so much time to get up to code? What are the challenges?

MARGOLIS: Yeah. So for bigger buildings, retrofits can be extremely expensive. They take a lot of time. And whether we demand those retrofits happen faster is kind of up to, you know, city officials and the public because they do take a lot of money as well.

CHANG: Yeah, a lot of money and a lot of time. Well then, I mean, practically speaking, for the average person, what are, like, next steps people can take if they live or work in a building that they think might not be structurally sound given everything that we've talked about? I mean, what can people actually do?

MARGOLIS: You know, find out if the building has been retrofitted here in Los Angeles. There's a website that you can search to tell you when it was built and if it has been retrofitted. For a lot of other cities, municipalities across the state, I don't think that's necessarily the case. So if it was built prior to the late-1970s and it's a concrete structure, just know that there is a possibility that it could come down in the next big quake.

CHANG: That is Jacob Margolis of LAist news. Thank you so much, Jacob.

MARGOLIS: Thank you.

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