Short Wave - Can We Predict Earthquakes? (Hint: No)

Episode Date: July 26, 2021

It's a listener questions episode! Chuck, Short Wave fan, asks, "What is the current state of earthquake prediction systems?" For some answers, Emily Kwong chats with Wendy Bohon, a geologist and Senior Science Communication Specialist for the Incorporated Research Institutions for Seismology (IRIS). To look at real-time seismic data from hundreds of locations around the globe, check out the IRIS Station Monitor. Have a question you want us to try answering? Email us at [e-mail] pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. NPR health correspondent Rithu Chatterjee here with Emily Kong. Hey, Emily. Hey, hey, Ritu. So today we've got something very exciting for everyone. It's a listener questions episode. Yes, I always love these. And we haven't had one of them in so long.

Thank you for sending us all your questions. Shortwave listener Chuck writes, love your podcast. I've learned and laughed. How about looking at the current state of earthquake? prediction research, a number of countries have been cooperating to get closer to a very, very difficult goal. Cheers. Great question, Chuck. Love the punctuation at the end. Cheers.

And so, Emily, you spoke to someone who knows a lot about the latest in earthquake science. Yeah, I did. Her name is Wendy Bohan. Now she's a geologist who studies earthquakes. But back in the late 90s, she was an actress, living in Los Angeles. Wow, an actress turned geologist. Yeah, it's a very careful. California story. So in her 20s, one night around like two in the morning, Wendy's fast asleep in her bed when all of a sudden a surfboard falls on her head. And that's my first sort of memory. I woke up to it and it was so loud. Car alarms are going off and you can hear the building

creaking. And one of Wendy's roommates had this little white rabbit. It had jumped into the toilet and started screaming. And I don't know if you've ever heard a rabbit scream, but it raises the hair on the back of your neck. And I run out and I'm like, what's happening? And my roommate Tom comes out and he's like, it's an earthquake. Oh my gosh. Did everything? Was everyone okay?

Yes, Rabbit, roommates and Wendy were all fine. Although she says that you could feel the aftershocks rolling in for hours after that. Wow. Yeah, that earthquake is now known as the Hector Mine earthquake, a magnitude 7.1 that originated in a remote part. of the Mojave Desert. So the resulting damage to populated areas was pretty minimal. But this whole experience left a lasting impact on Wendy and a new motivation. This mixture of just intense fascination and a little bit of fear. You know, I wanted to understand. That's my way of approaching things that are frightening to me, is to understand them and to research them. So eventually Wendy left

acting behind and got a master's and a PhD in earthquake, geology. Although she definitely puts her theater training to use in her science communication work around earthquakes. The perfect person to answer our listener question. So what did she say when you asked her about earthquake prediction? Okay, so I rarely toss a scientist a yes, no question, but I did with Wendy. Yes, no, is there absolutely any way to predict an earthquake? No. And anyone who tells you differently is selling something. And by predict, I mean, give a very localized location and a very specific time. So we just can't do that.

Wendy told me we don't really know when an earthquake will start or even stop. The science isn't there yet. We can't say we can predict these things. But we can detect them once they start. And that's what we're going to hear about today on the show. So after the break, Emily's conversation with Dr. Wendy Bohan about the systems we haven't placed detect, not predict earthquakes. You're listening to Shortwave, the Daily Science Podcast from NPR.

So my conversation with Wendy Bohan, geologist slash science communicator, started with the basics. First, what is an earthquake? Okay, so the most common type is a tectonic one. And that's when the massive plates of rock on the surface of the earth move and they get stuck at their edges. Friction holds them there. But stress builds up. And eventually the motion of the plates overcomes that friction, causing the rocks to break and slide. What we think of an earthquake are the waves that come off of this breaking and sliding. So when the rocks break, they produce energy in the form of waves that travels both across the earth's surface and through the interior of the earth.

That's the shaking that we think of as earthquakes. But the earthquake itself is actually the rocks breaking. And that seismic data is gathered by organizations around the world. including U.S. universities. Wendy works at a consortium of over 100 universities here in the U.S. It's called the Incorporated Research Institutions for Seismology, or Iris, for short. But no matter who's gathering the data, they all use pretty much the same fundamental tool to detect earthquakes. The instruments are unbelievably cool.

They're called seismometers, and there are thousands of them all over the world. We place them in basically anywhere that we can. We do it strategically, usually around areas that have active faults. But there's also caches of instruments that can be used after an earthquake happens. So scientists will get those instruments and we'll deploy them or put them out near where a big earthquake has just happened so that we can learn more about what's happening underground. So you can think of every seismometer, almost like a pixel and a camera, right? So the more pixels you have, the more scientific instruments that we have out, the higher resolution we can see into the ground. So these instruments, can you describe like how they're installed and then who is babysitting them?

Like what are they looking for? So there's lots of different kinds of seismic instruments. The scientific kind are generally putting a big hole in the ground, sometimes installed in concrete, depending on where you are. Sometimes they're just dug down. what they're looking for is anything that shakes the ground. And these suckers are very, very sensitive. They can detect changes in the ground that are like the size of a human hair across. And so we can detect things far beyond earthquakes.

Earthquakes all over the world. Yes, absolutely. We can detect hurricanes because when hurricanes happen, they cause bigger waves and these waves drum on the ocean floor, which basically creates surface waves very similar to the waves from an earthquake. And we can detect that all across the United States, for instance, when they're coming up towards the East Coast. We can detect when a tree falls. We can detect changes in wind. So lots of creative uses of what we used to think of as the noise or the thing that was getting in the way of us measuring the earthquakes. What's the mechanism inside these seismometers that has gotten so sensitive? It can detect things like that.

Now it's electric. It's based on the idea that you have, kind of like a pendulum that's hanging, and then the seismometer is attached to the ground. So the idea is that the seismometer moves with the ground, but the pendulum stays still. And so that pendulum can measure how much the ground has moved. So advances in the technology, advances in the electronics have allowed us to really detect, you know, much more sensitively

and also a lot more about like the different directions that the ground can move. Because an earthquake doesn't just shake the ground back and forth. You know, you get an upward. thrust, a sideways push, a downward drop, and then a sideways push in the other direction. The ground's moving in all kinds of different ways. It's important for us to know and record all of those different aspects. What signals, well, first, so there's this network of seismometers that exist throughout the U.S. to detect earthquakes. Is that right? Throughout the U.S. throughout the world. We have the global seismic network, which is maintained by Iris and the U.S.GS, U.S. Geological Survey. And that's like 150 to 200 instruments

that are around the world. We have networks in the United States. Other countries have their own networks. And then there are also smaller regional networks like the Pacific Northwest network. And most of the data from most of these networks gets fed into the Irish Data Management Center. And so it's open source for anyone in the world to use. Very cool. Okay. So talk me through earthquake alerts and how they happen, how they go from these sites into people's phones to alert them, to earthquakes and how much lead time is possible? Sure.

So when an earthquake happens and it sends the waves out, we need at least three seismometers to detect it. And very quickly we can get an estimate using mathematical algorithms and things about the magnitude of the earthquake and also the level of shaking. And so all of that information gets sent from the seismometers to the data center with the USGS and their partner organizations. Then they decide automatically, it's not like a person deciding, whether or not that earthquake meets the standard that it's going to potentially cause damage or people need to know. Then that will send alerts out to people in the area. And so you could get, you know, between a few seconds of warning, sometimes even as much as

as 30 seconds or a minute of warning. And people will say, you know, well, who cares about 10 or 15 seconds? I can tell you, you would care if you were getting LASIC eye surgery. You know, you would care if you were in the dentist chair. So there's other things we can do with that much warning, like slow down trains to prevent derailments. We can open firehouse doors so that the emergency response equipment doesn't get stuck inside if the doors are jammed during the earthquake shaking. So there's, you know, things that we can do both as individuals and as, you know, emergency response personnel, people that are involved in public safety can use these alerts to help keep people in property safe. Okay. Okay. Now, what is the level of just international collaboration these days to understand and share earthquake data? Like, how would you grade the current state of global earthquake science?

I do. Well, you know, we, we at Iris maintain the database, and that's open science. We want this science to be open and accessible to everyone. Public citizen, researcher, anywhere, anybody in the world can access that data. So that's huge, right? Open access. data in science is not always the norm. Also, researchers are really working together quite a bit, and things like Twitter have really, really helped with that. So here's an example. After the 2019 Ridgecrest earthquake that happened in California, which was actually the largest earthquake to happen in California since Hector Mine, it was a magnitude 7.1 out in the desert. There were some folks from the California Geological Survey that were out surveying where the ground was broken. And some folks in France had satellite data that showed them areas where there was deformation in the ground. And so through Twitter, these French researchers were sending

information to these American geologists that are out looking for the rupture saying, okay, go to this coordinate, go to this coordinate, this is where these things are. So people are really working in real time to coordinate responses. So I'm hopeful that as these early career scientist and mid-career scientists are reaching across the ocean and starting to talk to different research groups, that great collaborations will come out of that because science is not a solitary endeavor. I think that is very true. Wendy, thank you so, so much for talking to us about your work and where you want to see things go in the future. Oh, thanks for having me. It's been great chatting with y'all. Thanks to listener Chuck for writing in. If you have a science question,

you'd like us to answer, don't hesitate, send it our way. We might use it in a future episode. You can email us at shortwave at npr.org. Today's episode was produced by Indy Kara and Rebecca Ramirez, edited by Viet Le and fact checked by Burley McCoy. The audio engineer for this episode was James Willits. Thanks for listening to Shortwave, the Daily Science podcast from NPR.