Nature Quest: The Earthquake Prediction Problem

Summary

Short Wave – "Nature Quest: The Earthquake Prediction Problem"

Hosts: Emily Kwong and Hannah Chin
Date: November 25, 2025
Duration: ~15 minutes

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Episode Overview

This episode of Short Wave takes listeners on a "Nature Quest" to explore the challenge of earthquake prediction, focusing on the Pacific Northwest's looming "Big One." Producer Hannah Chin (Portland native) leverages her "producer privilege" to investigate why—despite deep knowledge about the likely impact of major quakes—scientists still cannot say when the next catastrophic earthquake will come. The hosts delve into geology, seismology, tsunamis, folklore, and the practical responses people can take, all while maintaining Short Wave’s signature blend of approachable science and wry humor.

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Key Discussion Points & Insights

1. The Cascadia Subduction Zone and “The Big One”

• Cascadia Subduction Zone: An underwater fault stretching from Canada to Northern California.
• Residents, especially in Portland, live with the anxiety of “the Big One”—a potentially magnitude 8 or 9 earthquake.
• First-Person Experience:
  • "Portland is not a hotspot for earthquakes... But as long as I can remember, Portlanders have known that an earthquake is coming. When we talk about it, we call it the Big One." – Hannah Chin [00:48]

2. What Would a Massive Earthquake Feel Like?

• Expert: Diego Melgar, Director of the Cascadia Region Earthquake Science Center
  • "You would feel shaking, where it's difficult, maybe even impossible for you to stay standing for anywhere between one or three minutes. Start counting right now and realize how long that is." [01:39]
  • Massive infrastructure damage: bridges collapsing, landslides covering major roads, utility failures, soil liquefaction [01:51].

3. The Impossibility of Earthquake Prediction

• Despite knowing a lot about the effects of earthquakes, predicting their timing remains out of reach.
• Expert: Chris Goldfinger, Marine Geologist and Paleoseismologist, Oregon State University
  • "Prediction is sort of, in the science world, as we call it, the P word. We just don't really even speak about it because nobody can do it." [02:34]
• The hosts and experts discuss the humility and frustration around this scientific limitation.

4. How Do We Know a Big Quake Is Past Due?

Clues in both Geology and History

• Ghost forests and sand deposits on the Oregon-Washington coast provide geological evidence of past major events [04:37].
• Japanese Historical Records:
  • The "orphan tsunami" of January 26, 1700, recorded by Japanese scholars who noticed a tsunami with no local earthquake source [05:09]. -:Chris Goldfinger:
    • “This tsunami arrived out of nowhere with no earthquake to go with it, no warning. It killed a few people, destroyed some boats…and they had written records of this.” [05:33]
• Detective Work:
  • Modeling linked the orphan tsunami to Cascadia, allowing an exact dating of the last major Northwest quake: Jan 26, 1700, about 9 p.m. [06:12].

5. Earthquake Timing: The “Chaotic Turkey” Metaphor

• Averages are Misleading:
  • Magnitude 9 earthquakes happen every ~500 years on average, but intervals can vary wildly.
  • "Earthquakes can cluster in time…It is not the case that they happen ‘500 years, nothing, earthquake.’ That’s not how Earth works. I wish it were." – Diego Melgar [07:04].
• Memorable Metaphor:
  • Chris likens earthquake timing to turkey in the oven with no thermometer or timer:
    • “You have no way of measuring when the cycle started or how far into it you are or how cooked it is.” [07:56]

6. What CAN Scientists Predict?

Understanding Effects, Not Timing

• Excellent ability to model and predict tsunami size, shaking patterns, and infrastructure risk scenarios [08:35–09:04].
• How?
  • By reading sediment core samples—like tree rings for the landscape.
  • Tina Dura, Coastal Geologist and Paleoseismologist, Virginia Tech:
    • "When we have a big Cascadia earthquake, tsunami washes in sand and deposits it on these marshes... And in some of these marshes, we have up to a 7,000 year record of past earthquakes.” [09:15 and 09:35]
• The interplay of rising land (tectonic uplift) and the sudden, dramatic changes after a quake.
  • The next quake could cause land to drop by up to 2 meters in minutes, leading to sudden, severe flooding—especially in low-lying coastal communities [10:34–10:47].

7. Linked Faults: The Domino Effect

• Cascadia Subduction Zone and California’s San Andreas Fault are “seismically linked.”
• Cascadia could trigger quakes on San Andreas and vice versa—“a big bad set of dominoes, just like tipping down the West Coast.” [12:21]

8. Hope: Earthquake Early Warning Systems

• Technology has progressed: Early warning networks with thousands of sensors can detect the tiniest initial tremors.
  • "We need seismometers, sensors that feel the first teeny Tiny vibrations." – Diego Melgar [12:46]
• Within 15–20 seconds of the first signals, emergency alerts can go out to phones and sirens, giving people precious—but brief—time to seek cover [13:36].
• "Even a little bit of advanced warning could be the difference between life and death." – Emily Kwong [13:43]

9. Knowledge is Power: What You Can Do

• Armed with accurate knowledge about earthquake and tsunami risk, people and communities can prepare.
  • "Knowledge is power, and I'd rather know that these are the challenges we're facing... Because armed with that knowledge, I can develop goals and objectives." – Diego Melgar [14:02]
• Personal and community preparation are key: planning, local networks, pushing for safer buildings and emergency plans [14:18].

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Notable Quotes & Memorable Moments

• “Prediction is sort of, in the science world, as we call it, the P word. We just don't really even speak about it because nobody can do it.” – Chris Goldfinger [02:34]
• “You would feel shaking, where it's difficult, maybe even impossible for you to stay standing for anywhere between one or three minutes.” – Diego Melgar [01:39]
• “Earthquakes are like chaotic turkeys.” – Emily Kwong, riffing off Chris Goldfinger’s metaphor [08:15]
• “The tsunami arrived out of nowhere with no earthquake to go with it, no warning.” – Chris Goldfinger [05:33]
• “15 to 20 seconds... even a little bit of advanced warning could be the difference between life and death.” – Emily Kwong [13:43]
• “Knowledge is power... I'd rather know that these are the challenges we're facing.” – Diego Melgar [14:02]

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Key Timestamps

• 00:48–01:19: Hannah explains Portland’s anxiety about “the Big One.”
• 01:39–01:58: Diego Melgar on what a major quake would feel like.
• 02:34: Chris Goldfinger on why scientists avoid the word “prediction.”
• 05:09–06:12: The orphan tsunami in Japanese records leads to exact dating of last Big One.
• 07:04: Explanation of why average intervals are misleading.
• 07:56: Chris Goldfinger’s turkey-in-the-oven earthquake analogy.
• 09:15–09:35: Tina Dura on reading sediment cores for quake history.
• 10:34: Sudden land drop and flood risk explained.
• 12:21: How Cascadia and San Andreas faults can trigger each other.
• 12:46–13:36: How the West Coast’s earthquake early warning system works.
• 14:02: The vital importance of knowledge and community action.

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Final Takeaways

• Earthquake timing is fundamentally unpredictable, but modeling of impacts has advanced immensely.
• Community preparedness makes a difference: knowledge, planning, and robust public safety advocacy matter.
• Early warning tech is improving—but every second counts.

The episode leaves listeners alert but empowered: we may not know when the Big One will come, but we can be prepared for what it will bring.

Transcript

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[Emily Kwong]

You're listening to Short Wave from npr. Hey, shortwavers. Emily Kwong here and Hannah Chin with this month's installment of NatureQuest.

[Hannah Chin]

And Emily, full disclosure, I'm doing something a little bit selfish today. Instead of answering a real listener question, I'm using my producer privilege, TM to investigate a question that I've had for a while about earthquakes.

[Emily Kwong]

Okay, tell me more.

[Hannah Chin]

So I'm from Portland, Oregon, and Portland is not a hotspot for earthquakes. We just don't experience them multiple times a year, you know, the way Californians do. But Portland is next to the Cascadia Subduction Zone, which is this underwater fault line in the Pacific Ocean that stretches from Canada all the way down to Northern California. And as long as I can remember, Portlanders have known that an earthquake is coming. When we talk about it, we call it the Big One. The Big One. The Big One.

[Emily Kwong]

This sounds kind of scary because I always picture, you know, Pacific Northwest is very like, chill. This is the opposite of chill.

[Hannah Chin]

It is the opposite of chill. So I called up a seismologist. His name's Diego Melgar, and he's the director of Crescent, the Cascadia Region Earthquake Science Center. And I asked him, like, what would an earthquake this big feel like?

[Diego Melgar]

You would feel shaking, where it's difficult, maybe even impossible for you to stay standing for anywhere between one or three minutes. Start counting right now and realize how long that is.

[Hannah Chin]

Scientists say this earthquake, it'll demolish buildings, rupture utility lines, liquefy soil.

[Diego Melgar]

We might get significant collapses of bridges and any old infrastructure. We would get thousands of landslides across the region, most of them covering major thoroughfares, especially in places that are very steep, like the coast ranges.

[Hannah Chin]

But, Emily, even though we know so much about how this earthquake could affect us, we still know very, very little about when it's gonna happen.

[Emily Kwong]

We don't know when.

[Hannah Chin]

We can't predict it at all. One scientist I talked to, his name is Chris Goldfinger, and he's a marine geologist and paleoseismologist at Oregon State University. He said they don't even use that word.

[Chris Goldfinger]

Prediction is sort of in the science world as we call it, the P word. We just don't really even speak about it because nobody can do it.

[Emily Kwong]

The P word. We don't do that in earthquake science.

[Hannah Chin]

And listening to this, Emily. I was like, why is that right? Why do we know so many concrete details about certain parts of this looming disaster and then zero details about this other seemingly really crucial part of when is it gonna happen?

[Emily Kwong]

Today on the show, the earthquake prediction problem, what we know and what we don't about quakes like the big one and how the science is shifting under researchers feet. You're listening to Shortwave, the science podcast from NPR Foreign.

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[Emily Kwong]

Okay. Hand. Today we are talking about earthquakes and the difficulty of predicting them, which is kind of scary when it comes to the magnitude 8, the magnitude 9 ones, the big ones. But how do you know a big one is coming for the Pacific Northwest?

[Hannah Chin]

That's a great question. So first, there's geologic clues of past earthquakes in the landscape. There's what we call ghost forests, these thousand year old trees on the Oregon and Washington coast that seem to have been submerged in seawater really quickly. And then in other places, you can find sand deposits in the soil that must have come from big earthquakes. And second, there's also more specific records that we have, human records from somewhere clear across the other side of the world, Japan.

[Emily Kwong]

Oh, that makes sense because Japan is extremely earthquake prone. It sits at like the confluence of multiple tectonic plates.

[Hannah Chin]

Yeah, exactly. So when a big earthquake hits there, it's often followed by a tsunami wave. It goes like earthquake, tsunami, earthquake, tsunami. But in the year 1700 on January 26, Japanese scholars have all of these records of what they called the quote unquote orphan tsunami. Orphan because they didn't know where it came from. It just didn't seem to have a parent earthquake preceding it.

[Chris Goldfinger]

And this tsunami Arrived out of nowhere with no earthquake to go with it, no warning. It killed a few people, destroyed some boats and destroyed bales of rice in warehouses. And they had written records of this.

[Hannah Chin]

So this is Chris again, the seismologist. He says the Japanese records were really accurate down to the height of the flooding and the amount of the destruction. And using these records, it was possible for scientists to do some detective work and figure out where that big wave came from.

[Chris Goldfinger]

And so Kenji Sataki, a Japanese colleague, modeled the tsunami. You know, where did it come from? Did it come from Alaska or Kamchatka or Chile or wherever? And the only place that matched was.

[Hannah Chin]

Cascadia, which, Emily, again, is that fault line right off the Portland coast. So that research is how we know that the last great earthquake in the Pacific Northwest was January 26th, the year 1700, about 9pm that is so precise.

[Emily Kwong]

It's incredible actually that they were able to track the last, you know, big one in the region to that moment in time, 325 years ago.

[Hannah Chin]

No, it's really cool. And scientists have done more modeling. They've researched earthquakes in the area further and further back. They've talked to indigenous people who have told stories about these quakes for generations. And they've realized that Cascadia has these really big earthquakes, usually magnitude nines every 500 years on average.

[Emily Kwong]

Oh, then we're fine. Right. Because if the last big one was in 1700, that's way less than 500 years ago. So it's fine. Right.

[Hannah Chin]

So this is what I thought too, but Diego told me it's not that simple.

[Diego Melgar]

Earthquakes can cluster in time, so it can be that every now and then the Earth earthquakes happen in quick succession. So we could have a few magnitude nines, only 250 years apart, then maybe a thousand year period of calm, then a quick succession of other big earthquakes. So Even though it's 500 years on average, it is not the case that they happen. 500 years, nothing earthquake. 500 years, nothing earthquake. That's not how Earth works. I wish it were.

[Emily Kwong]

These tectonic plates are like, we don't follow rules, we don't observe patterns.

[Hannah Chin]

Yeah. So we could be due for a major earthquake or we could be fine for the next 500 plus years.

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Either or.

[Emily Kwong]

Okay.

[Hannah Chin]

Our other seismologist, Chris, he compared it to figuring out when your Thanksgiving turkey is ready. If all you did was stick it in the oven and walk away.

[Chris Goldfinger]

Somebody says, is it almost done? Well, I don't know. When did you turn it on? I don't Remember? And you see the oven sitting there at 350 and you go, well, how long has it been gone at 350? I have no idea. And you don't have a turkey thermometer either. So you have no way of measuring when the cycle started or how far into it you are or how cooked it is.

[Emily Kwong]

That sounds like how I cook. Point is, earthquakes are like chaotic turkeys.

[Hannah Chin]

Right. And just to complicate this a little further, Emily, because I know that's what you're dying to hear, we don't even know for sure that this will be a magnitude 9 earthquake. It could be a little bit smaller, catastrophic, but not quite that big. Okay, but here's what we do know.

[Diego Melgar]

We have really good idea of what the tsunamis are going to look like and what the shaking is going to look like. And that's actionable information that we put to use.

[Emily Kwong]

That's important because since earthquakes can cause tsunamis, knowing what different size earthquakes will do to the land, to the water, is really important for human health and safety.

[Hannah Chin]

Yeah. And so that's the second part of this story. There's all of these things about earthquakes that science can and does predict, like what could happen when the big one hits.

[Emily Kwong]

How do scientists figure that out? Just knowing, like, if it's a X magnitude earthquake, it will do this.

[Hannah Chin]

They look for clues from the past and they can find those in places like estuaries and tidal marshes.

[Tina Dura]

So when we have a big Cascadia earthquake, tsunami washes in sand and deposits it on these marshes. And that sand is then preserved in the stratigraphic record, so in the coastal sediments over time.

[Hannah Chin]

So this is coastal geologist and paleoseismologist Tina Dura. She works in the geosciences department at Virginia Tech.

[Tina Dura]

We actually go out there with a tube and push it down into the ground. And, you know, the oldest earthquakes are at the bottom of the record. And as you go up towards the surface in the sediments, you see the younger earthquakes. And in some of these marshes, we have up to a 7,000 year record of past earthquakes.

[Hannah Chin]

Tina showed me a picture of one of these sediment core samples. It kind of looks like a layer cake. You can see the marsh dirt and then the tidal dirt on top of it, and then the tsunami dirt. And then it goes all over again.

[Emily Kwong]

It's like reading tree rings. It tells the story of the geology. What does looking at a record like that tell her?

[Hannah Chin]

She told me that between earthquakes, basically, when there's pressure building up on these tectonic plates, it causes the land to rise. Which, for what it's worth, is part of the reason that climate driven sea level rise hasn't really affected the coastlines of the Pacific Northwest the way it has, say, the Gulf of Mexico, et cetera, because the land is rising along with the ocean. It's rising at about 1 millimeter a year.

[Diego Melgar]

Whoa.

[Tina Dura]

But of course, the next earthquake is going to reverse that. And this land level change, where it goes down is going to happen over minutes, and it's going to cause a sudden sea level rise of up to 2 meters.

[Hannah Chin]

Combined with the already existing tsunami waves that were predicted to have, you'd get flooding, a lot of flooding, mostly in low lying areas along the coast. The places that are flat and easy to build on, where there are already airports and fire stations and wastewater treatment plants. And unlike tsunamis, where the flooding comes in and then goes away. Tina said the combination of the land drop and the waves is going to mean a much more permanent change to the landscape.

[Emily Kwong]

So whole areas might stay flooded.

[Hannah Chin]

Yeah.

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Wow.

[Hannah Chin]

And the other thing that's important to know, Emily, is that this might not just affect the upper half of the West coast, it could also trigger another earthquake further south, the California big one. So just south of the Cascadia fault is this other tectonic plate boundary called San Andreas fault, and that one's responsible for a lot of earthquakes in California. Remember Chris Goldfinger? He's the paleoseismologist we heard from earlier.

[Emily Kwong]

Yeah, the one with the incredible Turkey metaphor.

[Hannah Chin]

Absolutely. So in 1999, through a clerical error, he and his research team ended up sailing too far south and taking a sample of the San Andreas fault. And as they were comparing these samples, one from the Cascadia fault and one from the San Andreas fault, they realized that all the events that these cores recorded were happening super close together, just time wise, which is super weird. Right. So they took way more samples, they got way more data, and they realized that the Cascadia and the San Andreas were what geologists call seismically linked. They have the potential to trigger earthquakes in one another.

[Emily Kwong]

That sounds like a big bad set of dominoes, just like tipping down the West Coast. Okay, so more flooding, more landscape change, bonus earthquakes. Is there anything else we should know about the big one? Like is it just gonna be, or are we just powerless in the face of it?

[Hannah Chin]

We are not. There's good news because in the past few decades, scientists have developed the technology to create an earthquake early warning system.

[Diego Melgar]

The idea is quite simple. We need seismometers, sensors that feel the first teeny Tiny vibrations.

[Hannah Chin]

Diego told me we have thousands of these little sensors located all throughout Washington and Oregon and California. And they're all just listening to the Earth, waiting to hear these tiny, tiny vibrations.

[Diego Melgar]

And using decades of research and models, we know that if the teeny, tiny vibrations look a certain way, then these teeny, tiny vibrations are not from a 5, they're not from a magnitude 6, they're probably from magnitude 8 or from a magnitude 9. And after a few of these seismic stations detect these teeny tiny vibrations, then all the logic algorithms and technology kicks in and the alert goes off by cell phones, by emergency sirens and so on. And it says, you know, earthquake drop, cover and hold on.

[Hannah Chin]

This entire early warning system can be activated in 15 to 20 seconds, totally automated, without any human action.

[Emily Kwong]

That's astonishing. I mean, 15, 20 seconds doesn't sound like a lot of time, but just even a little bit of advanced warning could be the difference between life and death, you know?

[Hannah Chin]

Yeah, exactly. And all the scientists that I talked to, they told me it's really good to know everything we can about how this big earthquake will play out, even if we don't know exactly when it'll play out.

[Diego Melgar]

This is the point in the conversation at which I tell people, knowledge is power, and I'd rather know that these are the challenges we're facing, that the tsunami is probably going to be this size, that the shaking is probably going to be this intense. Because armed with that knowledge, I can develop goals and objectives.

[Hannah Chin]

And Diego says that's the next step. Right. If you're in the Pacific Northwest and especially if you're in a coastal town, make sure you have those goals and objectives. Make sure you have a flooding plan. Ask your neighbors if they have one, because when this happens, it's likely that medical experts won't be able to reach everyone. So we're going to need to rely on other people in our communities. Find out whether your state agencies and local emergency managers have an earthquake plan or write a letter to your legislators and ask them to push for earthquake proof buildings and evacuation centers. Yeah, it's going to take time, but Diego told me we're making progress. We have everything that we need to prepare.

[Emily Kwong]

Hannah Chin, you have repped your region well to get ready for this. Thank you for bringing this to all of us.

[Hannah Chin]

Thank you so much for having me.

[Emily Kwong]

Troyvers, if you have a question about your local environment, open up your phone and record us a little voice memo about it. You know your feelings, your thoughts, your observations, and then email that voice memo to shortwavepr.org we will listen and may even build an episode around your question.

[Hannah Chin]

Also, if you want to learn more about earthquake science and seismometers, you should check out another episode we did a while ago. We'll link to it in the show.

[Emily Kwong]

Notes this episode was produced by Hannah and Rachel Carlson. It was edited by our showrunner, Rebecca Ramirez. Tyler Jones checked the facts and Kwesi Lee was the audio engineer.

[Hannah Chin]

Beth Donovan is our vice president of podcasting. And special thanks to Paul Lundgren and Suzanne Carbot, whose research and expertise helped inform this episode.

[Emily Kwong]

I'm Emily Kwong.

[Hannah Chin]

And I'm Hannah Shin.

[Emily Kwong]

Come back for more shortwave from npr. See you later.

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