Earthquakes Keeping Reno Up at Night

In recent weeks, a seemingly nonstop wave of small earthquakes has rattled the residents of Reno, Nev. Seismologist Diane DePolo says she spends a lot of time these days explaining what the tremors might mean.

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RACHEL MARTIN, host:

That was a lot of squid news!

MIKE PESCA, host:

We should tell listeners that Mark has a chart near his desk called Squidlants, and I just hope we never the next biggest one, the ginormous squid.

MARK GARRISON: It's coming. It's very deep, so they haven't found it yet.

PESCA: I'm sure it's not as tasty.

MARTIN: Thanks, Mark.

PESCA: For the past couple of weeks, Reno has been the shakiest little city in the world. Hundreds of earthquakes are rolling over the area, and they're growing in strength, which is weird. Earthquakes usually feature aftershocks, not slowly building rumbles. There are other characteristics to this earthquake sequence that have seismologists scratching their heads. Diane dePolo is with the Nevada Seismological Lab in Reno. Hi, Diane.

Ms. DIANE DEPOLO (Network Seismologist, Nevada Seismological Laboratory): Good morning.

PESCA: So what's shaking?

Ms. DEPOLO: Oh, actually, we were pretty quiet overnight. We had a couple of about magnitude threes last night just before and after 11 o'clock local time. And since then, I looked at the records this morning. It looks relatively quiet overnight. A few pops, but not as many.

PESCA: Enough to feel them if you were awake?

Ms. DEPOLO: I'm sure the residents that are right on top of them felt some of them overnight. But the largest out of the ones overnight from about 11 last night on were just before 11 and just after, they were high-magnitude-two to low-magnitude-three range.

PESCA: How weird is it to have slowly building, or maybe in varying degrees, all these little earthquakes, not followed by a big one, but maybe preceding a big one?

Ms. DEPOLO: It's not unheard of. We, very often in Nevada, have larger earthquakes that are preceded by smaller earthquakes. And this just is kind of weird because it's been going on, we're entering our third month right now, and these are the quakes started in February 21st, and they've been continuing. And we experienced our largest one of the sequence last Friday night.

PESCA: So, if you were to chart them, they're not - each one is not necessarily bigger than the last, but in general, it's an upward slope?

Ms. DEPOLO: Correct. The upward trend, we started out with small-magnitude earthquakes, less than magnitude one. And then we had those for a few weeks, and then we had some that were felt by residents that were still relatively small magnitude in twos. And then, a couple weeks later, we started getting a few in the threes. And then last week, on Thursday afternoon, we had two that were magnitude 4.1 followed by a 4.2 that were less than four minutes apart.

PESCA: And how big is a 4.2? Like, do plates fall off the shelf kind of thing, or how to we judge it?

Ms. DEPOLO: Residents were losing plates and figurines off shelves. Some pictures came off the wall. Slight, some cracking in some of the houses, like over doorframes.

PESCA: Yeah.

Ms. DEPOLO: But that's about the extent of the damage through the 4.1 and 4.2. We have magnitudes for the Friday night one. The local magnitude we got was 4.7. Some of moment magnitudes that have been calculated have gone up to about five, magnitude five, and residents did have some broken pipes and cupboards opening and all their glasses falling out, dishes falling out, still considered kind of minor damage.

PESCA: Yeah, it seems like, you know, an inconvenience, bordering on something that could be dangerous. So I was thinking, aside from, you know, sales of Faberge eggs and Hummel figurines plummeting, how else has if affected daily life there in Reno?

Ms. DEPOLO: The anxiety levels for the residents that are right over the top of the earthquake is getting higher. They start to feel something, and they wonder if it's going to stop or if it's going to continue. So they're on shaky ground. They're very nervous, and it's just trembling beneath them. So, if your ground's not stable, you're kind of like, oh, what's going to happen?

MARTIN: Diane, how many people live directly on top of those fault lines?

Ms. DEPOLO: We've got a couple of communities just west of Reno. One is Mogul, and there's probably a couple thousand people in Mogul. And just east of there, in the Somerset area, I spoke to a group of residents last night, and I think they said there are about 1,200 residents in that area. It's a new development, just west of town, and probably about 250 of them showed up at the talk last night.

PESCA: So are you like a counselor as well as a seismologist, calming people down or at least giving them the info?

Ms. DEPOLO: Trying to give them the info. A lot of the people in the lab right now that are talking to the residents feel more like psychologists than seismologists.

PESCA: Mm hm.

Ms. DEPOLO: We're just trying to help people understand what's going on, give them suggestions on how to prepare for the earthquakes, to make them feel like they can take a little bit of control of the situation, make their surroundings safer. So, if something bigger should happen, they'll get through it better.

PESCA: Well, have you pulled the charts of all the past earthquakes that have been measured around the world and seen - just kind of held the chart of your earthquake up to them and try to get a gauge on what might happen?

Ms. DEPOLO: I haven't held the chart for around the world. I did do - get a search for earthquakes that we had in the area.

PESCA: Right, which makes more sense because you're dealing with this same fault line, so it might be similar.

Ms. DEPOLO: We're trying to just kind of look at what's been happening in Nevada. And since we have a catalogue that goes back to about 1852, so that's kind of when the pioneers starting coming through Nevada, to have a record of when earthquakes were happening here.

And in the 150 or so years since 1852, the Reno area has experienced about 20 earthquakes of the same magnitude that we had on Friday night, that magnitude and above. Some of those magnitudes were up to magnitude 6.4. That occurred closer to the Reno area, as opposed to just west of Reno. That would be about the largest out of the earthquakes that I found in the search.

PESCA: Oh, so that might indicate that maybe it won't get that much worse.

Ms. DEPOLO: We are very hopeful that it won't get that much worse. I know the residents out there don't want any more. They just - can you turn them off?

PESCA: Right.

(Soundbite of laughter)

PESCA: You may have a misunderstanding of what a seismologist does. I want to know, is there concern that this is going to affect tourism? Because I know that's a very important industry in Reno.

Ms. DEPOLO: We've actually had some calls of - I had a call from a gentleman from Florida yesterday planning a vacation and worried about coming out. The felt area is really very localized to the west part of town, and people in other parts of Reno, other parts of the valley, have only felt the larger ones, and they've only felt them slightly.

So they kind of think, well, there's nothing really going on. But we do live in a very active state. We are the third most-active state if you rank them. Alaska is one. California is two. Nevada is right there behind them. We have hundreds of faults that crisscross the state, and many of them are active. So we can have an earthquake at just about anywhere in Nevada, any time.

We had an earthquake in February of this year, February 21st, in northeastern Nevada, the Wells earthquake. It was magnitude six and it was just a little bit east of the community of Wells. It damaged an old masonry part of town. A lot of buildings came down that were unoccupied at the time. They were undergoing renovation. A lot of the residents lost chimneys, but the community is coming through it. Nevada still has their pioneering spirit.

PESCA: Yes.

Ms. DEPOLO: They really pull together in the communities and just help each other out.

PESCA: And as long as the little red ball doesn't wind up in the red and then they get shaken out into black, I think you'll survive.

Ms. DEPOLO: We will survive.

PESCA: Diane dePolo, seismologist at Nevada Seismological Lab in Reno. Thank you, Diane.

Ms. DEPOLO: Thank you.

MARTIN: Hey, stay with us. Coming up on the show, the Supreme Court ruled that states can require voters to present a photo ID before they vote. We're going to delve into that story, coming up on the Bryant Park Project from NPR News.

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